I just bought a set of logitech x230's from bestbuy, and they are very good for this application. The subwoofer gives a very full sound unlike other cheaper computer speakers. They are on sale right now for about 40 bucks. On my personal cabinet, I used a similar setup with computer speakers. I spliced in car speakers into the speaker wires and I love it.
BTW, if you want a game that will bring out the bass in the speakers,
try ULTIMATE SPIDERMAN!!! It is one of the video pinball games. Not that great of a game, but man was I blown away by the sound! It is my test game for speakers. You'll know if you have the real deal or not.