It's really odd, I used to really dislike The Beatles, but recently I've grown to enjoy their stuff, although I still don't hold them on a Pedestal like so many others do. Vice-Versa, I used to really enjoy The Rolling Stones, but now I'm finding them harder to enjoy then I used to. I still <3 a few of their songs (Paint it Black, mainly) but some of the rest of their stuff is just starting to grind at me a bit.
As for bands I dislike: I've always disliked Poison. I don't like Motley Crue. I find them both really boring bands, and since their paticular genre is flooded with bands very simuliar to them, I just find other bands I'd rather listen to. "Every Rose has it's Thorn" might be just one of those songs that's been played 1 to many times on the radio. I think Elvis is a bit overrated. I can't say I like Lynard Skynard to much either. "Sweet Home Alabama" is ok once in a while, but otherwise it's annoying. I have a love/hate relationship with "Free Bird" (In the same way I don't really like "Stairway to Heaven"). The songs themselves arn't bad, but they're far to overrated in this day and age, and get radio/party play far to much for my liking. Those songs/bands have just lost their spark to me I guess.
(I can't really say I hate The Eagles though...)