Any metal group, with the exception of Sabbath, AC/DC, and Led Zep - although I don't consider them that. Any punk band. Most prog bands. Any Grunge bands. Disco, with a few exceptions. Same with Rap and Hip Hop. Any modern Country band or singer. The Hair Bands, the Boy Bands, the recent female singers that sound the same, from Britney to Madonna to J-Lo to Selena Gomez and all the rest - it's no wonder Paris Hilton thought she should put out an album, hers wasn't worse than the others. And now Taylor Swift has crossed over and joined them.
Metalica, Green Day, Motley Crue, any 'name' band that isn't easily recognized by their sound (i.e., been around for awhile and still manages to sound like everyone else).
I think Queen mostly sucks. James Taylor. Dio. How much time do we have?