I buy some stuff, to support a few artists and pretty much download the rest. Also, if I have ordered a CD I often download the music before my CD arrives.
Artists get money off of me for live performances.
If I buy music downloads, I don't use iTunes because I don't want to have 256kb/s m4a files. I'd rather have high quality MP3s.
Also, of the CDs that I do own, the copies that I have on my computer are copies that I've downloaded because it's easier than ripping them myself.