Yeah, you got a good point there. And I love Newegg... Every now and then I browse their pages and think about building a cheap but good system. I think I could do a P4-2.8GHz system for about $525.
Hmm... Case, around $30, mobo around $50, AMD Sempron around $60, RAM around $40 (PC3200 256MB), 64MB nVidia card with composite TV out (yellow plug) for about $50, 40GB 7200RPM hard drive, around $40, CDRW/DVD combo for about $30.... Assuming the case comes with a PSU, 400W or so, figure $250 for a basic box.
Basically this thing's gonna be a pretty DVD player to play Divx/Xvid AVIs burned to CD, as well as some other misc. tasks. It might get online at some point, or play simple games, but nothing fancy at all. It's gonna be hooked up to a TV.