Powersupply can make or break your system, don't skimp out on it, especially if you're using it for gaming. I use an Antec 430w (
http://www.newegg.com/app/ViewProduc...103-908&depa=0) haven't had any problems with it. My old PSU that crapped out on me was a 350 no name brand.
Another thing people like to skimp on is the CPU fan, I recommend a Cooler Master Aero (
http://www.newegg.com/app/ViewProduc...103-139&depa=0), these things are great, better then the Volcano's and way more quiet.