Best metal Riff??!!??!!?

Meh. Does anyone even know what "metal" means? Blah.

Smoke On The Water....is almost too slow to count as hard rock, geez. O_O

Queen's "We Will Rock You" has the best Classic Rock Riff, period. Just go to a damned basketball game sometime. ^_^

Best Punk Riff? "Anarchy in the UK," by the Sex Pistols. "American Idiot" from Green Day gets a nod too.

Best Rock Riff? (tie) It's either the opening riff from Van Halen's "Hot For Teacher" or the main riff from "Welcome to the Jungle" by The [original] Guns-n-Roses.

Best Old-School Metal Riff? Metallica's "One", easily. Although Megadeth's "Symphony of Destruction" gets a Guilty Pleasure Honorable Mention.

Best Nu Metal? "Last Resort" by Papa Roach...mainly because it's an almost exact replica of the riff from AC/DC's "Back in Black" at the start. The rhythm is virtually identical.

Best Recent Metal? Hmmm... In Flames. "Cloud Connected", and their album after that. They're obscure, but crispy as hell.

Disturbed and System of a Down both are good, but they rarely pay attention to the riff.

Hmmm...

Walk - Pantera

Crazy Train - Ozzy Osbourne

Smoke on the Water - Deep Purple

Laid to Rest - Lamb of God

Iron Man - Black Sabbath

Sweet Child O Mine - Guns and Roses

Awesome question..

Crazy Train

Smoke on The Water

Tool - Schism

majorly smoke on the water