Tough one...
Led Zeppelin, Pink Floyd, AC/DC. I also enjoy Motley Crue, VH and GNR.
Others... The Cure, early U2 stuff, The Cars. I also like a lot of the Stones stuff.
A band I really enjoy, and I think they should have been bigger than they were... Great White. Very underrated, in my opinion.
I can't listen to Rush. They're musically sound, but Geddy's voice ruins it for me.
As an aside, name some bands that you don't understand. For me, I've never understood the appeal of Eagles. They're boring. I have no use for Pearl Jam or The Foo Fighters, either. All hugely popular bands that I cannot listen to. The vocalist is usually make-or-break for me.
Apologies to aurora, we've gone off topic a bit here...