The main issue I had with his rig was the Phenom 1 (horrible overclockers). The 9800GTX is not BAD, but the 5770 would have been a better choice in my opinion.
The motherboard and Phenom 1 are the main problem, as they are not upgradable at all without completely replacing the motherboard and processor. Also, the Ram can't be re-used if you plan on doing a proper upgrade.
Still, this rig will chew up basically any game you throw at it, and for $500 I wouldn't expect much better. (unless of course you're talking about a Tech-forums build., you guys are CRAZY about getting some amazing machines for dirt cheap)
Not bad though, once again 6/10