I don't know enough about how to classify the different genres (little ignorant here!) but I like so many different types that I don't think I have a favourite to begin with!

I would say that I am the same though; the majority of my music collection falls under the vague umbrella "alternative." I guess anything that isn't popular [pop] music nowadays is deemed alternative?

Well, my favourite bands/music artists are:

16 Horsepower (Rock/Americana/Folk)
The Flaming Lips (Rock/Alternative)
Fleet Foxes (Indie/Alternative)
Aimee Mann (Rock/Alternative)

Those are the labels that my Windows Media Player have given those artists. ^^

I like what I like. :) I'm not ashamed of any of the music I listen too and not ashamed to let other people know what I listen to, unlike back when I was a teenager...