I'm a guitar player myself and don't really pay that much attention to bass parts, but I will do my best to think of some good ones.
Riffs:
Fade to Black - Metallica
Let it Go - Def Leppard
Money for Nothing - Dire Straits
I Ran - A Flock of Seagulls
Walk - Pantera
Basslines:
Money - Pink Floyd
Under Pressure - Queen
Maria, Maria - Santana
Swingtown - Steve Miller Band
Aerials - System of a Down