Like I was saying, you either spend $250, $500, or $1000.
I just spent $499 on an HP Athlon 3400+ with 200GB SATA drive & 512 MB RAM. Pretty good deal, but it sounds like some of the ram gets eaten by the onboard video.
Since I'm buying it on behalf of somebody else, I'm kind of happy that I really didn't spend any money. I'm going to try out the media center capabilities before I give it away though.