Any "artist" that is a rapper, especially Puff Wussie!!

I agree with most that's already been said:
Linkin Park
Limp Bizkit

But here are few more:
The White Stripes
The Vines
Weezer
The Grateful Dead (well, any hippie band)
The Darkness
Weird Al Wankerbitch (or however it's spelled)
Michael Jackson
Any and all boy bands
Any and all Brittney's (especially Ashley Simpson)

Seems like most bands who's name starts with "the" is automatically going to suck!!