I know what you mean. I seem to mainly like bands that I can't pidgeon-hole easily - Tom Waits, John Cale and Giant Sand spring to mind as having a variety of styles not only over their albums, but with the albums themselves.

I've ended up using "Rock" for anything vaguely mainstream, and "Alternative" for stuff that isn't. Mind you, I don't use the genre searches anyway, so it's all rather academic. I have a set of genre playlists into which I put entire artists, but this also leads to rather erratic mixes - I mean, Cale's "Eat/Kiss" soundtrack alongside his "Sabotage" live album?

Bryan.