Use this PSU calculator to help find out what the best wattage for you would be. If you require a 400-450 watt power supply (which I think you do) the general rule of thumb is you get what you pay for, and the psu is one of the most important things in your setup. Some good brands (they are pricey, but definately worth the extra cash) are Seasonic, Corsair, Antec, Silverstone etc. Try looking at this list for some quality 400-450 watt power supplies http://extreme.outervision.com/psucalculatorlite.jsp Also, if you're real on a budget try looking around on websites that might be selling some good power supplies used but in good condition. Hope this helps.