What PSU Wattage?

Here a tool on how to calculate your load use it

http://www.corsair.com/psufinder/default.aspx

400w would be minimum 500-600w would be ideal and you don't have to spend alot to get a decent one.
http://www.newegg.com/Product/Productcompare.aspx?Submi...
Note the OZC's are modular which is nice for cable management.
The NEO isn't modular and doesn't ship with a power cord(just use your old one)
You don't need one this powerful but the price is awesome.
OCZ Z-SERIES 650W 80+ Silver Certified 24PIN ATX 12V Afc Power Supply W/ 120MM Fan
Our Price: $56.86 USD
Savings Code 45236-1008. SAVE $37.92 off our regular price of $94.78 if you buy today! Special price ends 8/18/2010. Limit 1 per customer.
After Mail In Rebate: $36.86 USD
Save $20.00 with manufacturer's mail-in rebate!
Valid from Aug 11, 2010 to Aug 25, 2010 Limit 1 rebate(s) per customer. Other conditions may apply.
http://www.ncixus.com/products/?sku=45236&vpn=OCZZ650&m... Technology&promoid=1008

400 watt Corsair unit is more then plenty for your system You could run that system on lesser if you needed , but I wouldn't go under 400 watt. Whatever you do dont get suckered into to those cheap units rated for big power because you will be lucky to get half the power it says it has.

Antec Corsair, OCZ...