I have to admire Victor Wooten's virtuosity, but I'm not a fan of his mega-new age mumbo jumbo and slightly over-insane bass riffs.
For the same reasons, I admire Les Claypool, and the rest of Primus as well. I just can't listen to their music (minus the South Park theme song and "John the Fisherman").
I also highly dislike bands like August Burns Red (generally any band that doesn't have vocals, it has screams...), but I have to give them props for being one of the few bands in their genre to be very dynamic and precise musicians, instead of an endless-breakdown-band.
If solo artists count....I hate David Bowie. I really do. Not as a person, because he seems like a cool guy, but other than "Space Oddity" and "Under Pressure" (with Queen), I can't listen to anything he's done... However, he's reinvented his sound and persona so many times that a Schizophrenic would have a hard time keeping up, and that's led to his influence being all over pop music of several decades, which is an impressive feat, even for those who despise him.
and finally, I absolutely LOATHE Kiss. I hate how much of a sexist pig Gene $immon$ is, how lowest-common-denomenator their music is (how much simpler and immature can you get than "I wanna' rock and roll all night and party every day"... although Detroit Rock City is a good song, despite my dislike...), and that they have made more money than almost any band minus the Beatles for providing some of the least fulfilling music to listen to. But, all hate aside, I have to admire their work effort to put on a good
show, and their financial sense (primarily Gene's), both of which are top-level.
Now as to bands I hate with good reason: (no one said it's not allowed!

)
The Sex Pistols - No one could play, no one could sing, it was just stupid rebellion-for-rebellion's sake crap. Probably the soundtrack to the London riots of late, too...
Almost every "___-core" band. Once you get past August Burns Red and their lot, it all starts to sound like really, really bad, unprofessional copy-catting with no musicianship whatsoever...
Boy Bands. Just kill them all. NOW. Please take out BOYZIITHEBACKSTREETBIGTIMENSYNC............in whatever jacked-up anagram conglomeration they may be in now.