I'm with the guys above, get him a fairly decent PC, llano is a good choice, then get him a really nice monitor/speaker system since that's what he's mainly going to be using it for.
Definitely go to town on the peripherals, he won't feel like he got his money worth with a cheapo monitor and a mouse/kb like those. I would say go for a nice IPS display like the U2410, Aego M speakers, and a basic, quiet PC .The affordable all-rounder would work if you leave out the graphics card and cpu cooler. You'll need to change out the mobo for one that does integrated graphics, but I can't really imagine it getting much better for a general use PC. Good luck!
