My own musical tatstes have changed greatly over the years, for instance...
I used to be a big Jimi Hendrix fan, but now I prefer more acoustic orientated music like Donovan and Nick Drake. I used to despise 1980's corporate rock type stuff, but now find myself listening to early Foreigner(gasp!!!). I'm also a big fan of early Progressive Rock, something that would have made me vomit circa 1990.
Anyway, what music have you liked but now dislike, or what music did you use to dislike but now like?