How about Tom Hamilton's bass riff in "Sweet Emotion" by Aerosmith...arguably one of the greatest bass riffs of all time.
Also, can't forget Mr. Duff McKagan of Guns N' Roses. Back in the day, Axl would ask him to "give me some of that bass thing" before the beginning bass riff of "It's So Easy".
And of course, can't forget Sting of the Police. Most of their biggest hits are formed around bass riffs.