Elliott Smith
Billy Joel
They Might Be Giants
The Beatles
Jill Sobule
I expect Jonathan Coulton would be on here too if I'd heard more than a song or two of his.
I could actually go on and on, picking a top 5 is just too hard. I love music.
A lot of my favorite music is just random songs from various artists, too, with no particular extra affinity for the artist.. I loathe Christina Aguilera, for instance, but I think 'Beautiful' is pretty swell.
I like radiohead a lot, but don't own any of their stuff.