Will buy it if I hear good things about it from friends, but will sample their style first just to make sure.
Then I'll also just listen to mp3's to see what a band sounds like that I've never heard, just to find new music. If I like it, I'll buy it.
Won't burn CD's though, mainly because I kind of like having the full packaging.
Now bonus tracks released on albums I've already bought (which really does piss me off, I mean, their long term fans buy the album when it comes out, and they just screw them over by doing this) are fair game. I'll be fucked if I'm buying it again just for one track.