the ACTUAL tuning Pantera plays in is a quarter step down, yes, a quarter step. find 
that spot between half step down and standard and let that sucker sing!

what im going to do in this tab is show all the riffs, not how many times you play each, 
you should be able to realize when one ends and the other begins as long as you know 
the song. and they are also in order. if its confusing at all, message me for changes. enjoy.

key:
<>  artificial harmonic (pinch harmonics)
[]  natural harmonic
~   vibrato
h   hammer on
p   pull-off
/   slide
b   bend
r   release

clean riff 1 (main)
e--------------------------------------------------0-------|
B----------2----------0--------------0-----------2---2-----|
G--------2---2------4----4---------4----4------4-------4---|
D------2----------2--------2-----2--------2--0-------------|
A----4----------0------------------------------------------|
E--2--------------------------0----------------------------|

clean riff 2 (fill) this is the 2nd riff in the song
e-------------------------------------------------------0--------|
B----------2-------------0--------------0---------2-------2------|
G--------2-----2-------4----4---------4----4--------4-------4----|
D------2-----2-------2--------2-----2--------2--0-----0-------0--|
A----4------------0----------------------------------------------|
E--2-----------------------------0-------------------------------|

clean riff 3 (part where Phil sings "left in my misery")
e-----0-------0-------0-------0----------|
B-----3/5-----5\7-----7\9-----9\10-------|
G--4---/6-----6\7-----7\9-----9\11-------|
D----------0-------0-------0-------------|
A----------------------------------------|
E----------------------------------------|

clean riff 4 (rhythm)
e------2-----2--------2-----2--------2-----2---------2-----2-----------|
B--------5-----5--------4-----4--------3-----3---------2-----2---------|
G----------2-----2--------2-----2--------2-----2---------2-----2-------|
D----------------------------------------------------------------------|
A---4---------------4--------------4--------------4--------------------|
E---2---------------2--------------2--------------2--------------------|
                                                                       |
lead (distorted)                                                       |
e----------------------------------------5b6----------4b5--------------|
B---5~~-------------4~-------------3~-------------2--------------------|
G----------------------------------------------------------------------|
D----------------------------------------------------------------------|
A----------------------------------------------------------------------|
E----------------------------------------------------------------------|

clean riff 4 continued
e------2-----2--------2-----2--------2-----2-------------|
B--------5-----5--------4-----4--------3-----3-----------|
G----------2-----2--------2-----2--------2-----2---------|
D--------------------------------------------------------|
A---4---------------4--------------4--------------4------|
E---2---------------2--------------2--------------2------|
                                                         |
lead (distorted)                                         |
e-------7b8--------------9b10----------------------------|
B---5~~--------------------------------------<10>\\\\\---|
G-------------------8~-------------7~--------------------|
D--------------------------------------------------------|
A--------------------------------------------------------|
E--------------------------------------------------------|

clean fill
e--------------------|
B-------5------------|
G---4h6--------------|
D--------------2-----|
A----------2h4-------|
E--------------------|

distorted track (clean 1 and 2 play behind it listen to the song to know when to bend, 
each bend is a full bend)
e-------------------------------------------------9---9~\7~-----|
B--------------------------5b~~~~~~5brbrbrbrb-------------------|
G---------4b~~~~--4-2--------------------------/9---9-----------|
D----4~---------------2~----------------------------------------|
A---------------------------------------------------------------|
E---------------------------------------------------------------|

harmonized guitars:
guitar 1
e--10----10-12----12-14----14-16----16-17~~~------|
B-----12-------14-------15-------17---------------|
G-------------------------------------------------|
D-------------------------------------------------|
A-------------------------------------------------|
E-------------------------------------------------|
                                                  |
guitar 2                                          |
e-------------------------------------------------|
B--3---3-5---5-7---7-9---9-10~~~------------------|
G----4-----6-----7-----9--------------------------|
D-------------------------------------------------|
A-------------------------------------------------|
E-------------------------------------------------|

distorted main riff                                   1st, 2nd time
e---------------------------------------------------|--------------------|
B---------------------------------------------------|--------------------|
G---------------------------------------------------|--------------------|
D--2------------------------<9>-----2---------------|--------------------|
A--0-0-0-0-0-7-6h7-<8>--7h8----7h8--0-0-0-0-0-7-6h7-|-<8>--6h7---<6>-----|
E---------------------------------------------------|-----------8----7---|


3rd time
e-------------------|
B-------------------|
G-------------------|
D-------------------|
A--<8>--6h7----2-3--|
E-----------8--0-1--|

main riff 2                         4th time ends with..
e-------------------------------|   |------|
B-------------------------------|   |------|
G-------------------------------|   |------|
D--------2-------4-------5------|x4 |--4---|
A--4-----0-0-0-0-2-2-2-2-3--2-3-|   |--4~--|
E--2-2-2--------------------0-1-|   |--2~--|

at this point the song jumps back into the clean 1 and 2 riffs

prechorus
e--------------|-----------------------------------------|
B--------------|-----------------------------------------|
G--------------|---------2---------2---------2-----------|
D--------------|-----------2-------------------7--7------|
A--------------|-4---3/4---0---3/4---2---3/4---5--4------|
E--/pickslide\-|-2-------------------0----------------0--|

prechorus ending
e----------------------------|
B----------------------------|
G----------------------------|
D--7-7-7--7------------------|
A--5-5-5--4--7--7-7/---------|
E------------4--4-5/---------|

chorus is the same as main riff

presolo riff

e-------------------------------|
B-------------------------------|
G-------------------------------|
D--2-----2-----2-2-----2-2------|
A--0-----0-----0-0-----0-0------|
E----0-1---0-1-----0-1-----0-1--|


GUITAR SOLO
                       hold----|   hold----------|
e----------------------5---5p4~------9---9~------|
B---3p2h3h5/7\5p3p2~-----2~----------------------|
G---------------------------------/9---9~--------|
D------------------------------------------------|
A------------------------------------------------|
E------------------------------------------------|

e------12---10~--10p9----9---------------------------|
B---------9-----------12---10~---10-9-8-7-6-5h6-7~---|
G--/11-----------------------------------------------|
D----------------------------------------------------|
A----------------------------------------------------|
E----------------------------------------------------|

e--7---7---------7------5---------|
B----7---7b~-------7b~~~~~~r-5----|
G---------------------------------|
D---------------------------------|
A---------------------------------|
E---------------------------------|

e------------------------------9h10h12p10p9h10/12-|
B--------------9h10h12-9h10h12--------------------|
G--/11-9h10h11------------------------------------|
D-------------------------------------------------|
A-------------------------------------------------|
E-------------------------------------------------|

e-10h12h14p12p10/12h14h16p14p12/14h16h17p16p14-19b--17----17------|
B------------------------------------------------------19----19---|
G-----------------------------------------------------------------|
D-----------------------------------------------------------------|
A-----------------------------------------------------------------|
E-----------------------------------------------------------------|

e--19--16-16---------------------------------------------------------|
B------------17~~----------------------------------------------------|
G--------------------------------------------------------------------|
D-------------------------------------------------------13-14-15-16--|
A-------------------------------12-13-14-15-13-14-15-16--------------|
E-------------------12-13-14-15--------------------------------------|
                    PALM MUTE~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~|

e-------------------------|
B--14-------14-------14~--|
G--14--x-x--14--x-x--14~--|
D------x-x------x-x-------|
A-------------------------|
E-------------------------|

e----------14---------------14---------------14-----------14----14------|
B-------14----17p14------14----17p14------14----17p14-17b---17b----17b--|
G--16b--------------16b--------------16b--------------------------------|
D-----------------------------------------------------------------------|
A-----------------------------------------------------------------------|
E-----------------------------------------------------------------------|

e--21p14-17-21p17p14-21p17-20p14h17-20p17p14-20p17-|
B--------------------------------------------------|
G--------------------------------------------------|
D--------------------------------------------------|
A--------------------------------------------------|
E--------------------------------------------------|

e-19h20p19p17----17-19h20p19p17----17------|
B-------------19----------------19----19~--|
G------------------------------------------|
D------------------------------------------|
A------------------------------------------|
E------------------------------------------|

e-----14-16-17p16p14----14-19p17p14----14-17p14-17p14----14-|
B-/17----------------17-------------17----------------17----|
G-----------------------------------------------------------|
D-----------------------------------------------------------|
A-----------------------------------------------------------|
E-----------------------------------------------------------|

e-------------------------------------------------------------|
B--17p14-17p14----14-15p14-15p14----14------------------------|
G--------------17----------------16----16p14-16p14----14------|
D--------------------------------------------------16----16~--|
A-------------------------------------------------------------|
E-------------------------------------------------------------|

use a tremelo bar to play this last part right. {} symbolizes bar dives. you'll have to 
listen closely for timing. 
e-------------------------------------------------------------------------|
B-----------dive------------|~~dip the trem here~|------------------------|
G--14h16p14-{14}-13p11/10-9-11p10p9-11p10p9-10p9p8-9{9}{9}p7-{<6>}--------|
D-------------------------------------------------------------------------|
A-------------------------------------------------------------------------|
E-------------------------------------------------------------------------|

after the dive bomb (listen for palm mutes and rhythm, this whole riff is about groove)
e--------------------------------------------------------------------------|
B--------------------------------------------------------------------------|
G--------------------------------------------------------------------------|
D-----------2----------4----------5---------------2----------4-------------|
A--4--------0-0-0--0-0-2-2-2--2-2-3--2-3-4--------0-0-0--0-0-2-2-2-2-3-3-3-|
E--2-2--2-2--------------------------0-1-2-2--2-2--------------------------|

e--------------------------------------------------|
B--------------------------------------------------|
G--------------------------------------------------|
D-6--5--2-----------2----------4----------5--------|
A-4--3--0--4--------0-0-0--0-0-2-2-2--2-2-3---2-3--|
E----------2-2--2-2---------------------------0-1--|

e----------------------------------------------------|
B----------------------------------------------------|
G----------------------------------------------------|
D----------2----------4-------------6--5-----6--5----|
A-4--------0-0-0--0-0-2-2-2-2-3-3-3-4--3--6--4--3--6-|
E-2-2--2-2--------------------------------4--------3-|

now it kicks into the main riff again. the end has variations:

e-------------------------|-------------------------------|
B-------------------------|-------------------------------|
G-------------------------|-----------------------<4>-----|
D--2---------2-1h2-<3>----|--2---------2-1h2-<3>----------|
A--0-0-0-0-0--------------|--0-0-0-0-0--------------------|
E-------------------------|-------------------------------|

and here come the bar squeals! if you dont know how to do them copy paste this link into 
google, http://www.youtube.com/watch?v=wgtZ7oOCmdM

*minor note* 2.25 means rip a natural harmonic a quarter way to the 3rd fret
e-------------|-------------|-------------|
B-------------|-------------|-------------|
G--[4]--------|--[2.25]-----|--[2.25]-----| fade out.
D-------------|-------------|-------------|
A-------------|-------------|-------------|
E-------------|-------------|-------------|

thats the song! and one of Dimebag's best.