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.