Nice box, IMHO. If your son is ONLY an online gamer then 80 GB on the hard drive might be enough.
One recommendation from a scarred veteran - pay the money for a good antivirus package and download a decent anti-spyware package. It pays dividends.
I'd say spend some extra money and get a Media Center PC with at least 250 GB HD. That should hold nearly all of the games, music and TV shows you care to store on it and if room runs out, you can always add a cheap external hard drive to store even more stuff. And don't forget USB hubs and peripherals.
(Denny Crane: "I Don't Want To Socialize With A Pinko Liberal Democrat Commie. Say What You Like About Republicans. We Stick To Our Convictions. Even When We Know We're Dead Wrong.")