UPDATE: this is long overdue, but some of the comparisons here should be disregarded, and others are missing entirely. Please compare these songs instead:
e1m1 - "Hooked" by D.R.I.
e2m6 - "Going After Newt" by James Horner
e3m2 - "Body Count's in the House" by Body Count
MAP02 - "I Can't Go For That" by Hall & Oates (0:59)
The comparisons in this video are:
e1m1 - "No Remorse" by Metallica
e1m4 - "Rise" by Pantera
e1m6 - "Sanity Obscure" by Believer
e2m1 - "Big Gun" by AC/DC
e2m2 - "Mr. Doctor" by Devil Doll
e2m3 - "Regular People (Conceit)" by Pantera
e2m9 - "Mouth for War" by Pantera
e3m3 - "Behind the Crooked Cross" by Slayer
e3m8 - "Sargent D & the S.O.D." by S.O.D.
Map01 - "Hangar 18" by Megadeth
Map02 - "Samba Briza" by Atheist
Map07 - "South of Heaven" by Slayer
Map09 - "Sex Type Thing" by Stone Temple Pilots
Map10 - "After All (the Dead)" by Black Sabbath
Map18 - "This Love" by Pantera
Map23 - "Them Bones" by Alice in Chains
Map25 - "Angry Chair" by Alice in Chains