Budget, Upgrade-able Gaming Computer

[Wrobichaud]

Hey guys, my friend's interested in building a gaming computer, only thing is, he only has around $500 cad to spend (before taxes and shipping). Its been awhile since I built mine (year and a half) and I'm too busy to look up what the newest best-bang for your buck parts are. If someone could shed some light on some decent, yet upgrade-able parts from Canadian stores (newegg.ca, tigerdirect.ca, ncix.com) that would be awesome.

Thanks, Wil