With you on that one choucas09 :D
I'm also with Twinfan on what is or isn't a "riff" - hard to draw the line though. And like Philly says about Blackmore, who for me was an "all-star" riffer, you can't really pick many of them out as recognisable in their own right! I have to admit that the "Smoke on the water" intro is a part of "riff history", but his playing under the verses is more jaw-dropping for me, both in its simplicity and effectiveness.
Anyway "Riffs" that I go for a lot:
Tie Your Mother Down - Queen
Gone Shooting - AC/DC
Love me like a reptile - Motorhead
I Feel Fine - The Beatles
Living Loving Maid, Bring it on home, The Ocean, etc, etc - Led Zeppelin
Bought and Sold - Rory Gallagher
Smoke Stack Lightnin - Howlin Wolf
Shakin all Over - Johnny Kid and the Pirates
There's also loads of "fab and groovy" jangly riffs on 60s stuff - the Searchers, the Hollies, etc... or the Georde Harrison parts on things like Ticket to Ride... They don't show up as "riffs" like us rockers think of, but they are mighty fine :D