Porcupine Tree - Shallow
Tool - Jambi (Intro riff
)
Slayer - Chemical Warfare
AC/DC - It's A Long Way to the Top...
Black Sabbath - Supernaut
In Flames (Kick-ass riffs factory) - Colony main riff / Swim / Versus Terminus (At 02:12)
Scorpions - The Sails of Charon (Testament's version is awesome as well)
Almost every riff on Van Halen's debut album. I'm the One stands out.
Disarmonia Mundi - Common State of Inner Violence
A lot of riffs in Judas Priest's Screaming for Vengeance
CKY - 96 Quite Bitter Beings main riff
Alice in Chains - Nutshell
Liquid Tension Experiment - Paradigm Shift Initial riff / Everything in Acid Rain
Karnivool - Deadman intro / Roquefort
Meshuggah - Bleed (I don't give a fuck if it's their most known song, it kicks ass)
Unearth - Zombie Autopilot / Grave of Opportunity