If you are hooting from Tradepac, can go for i5-3470 & Asrock B75 Pro 3M @ $334.
Hard disk change to Hitachi Deskstar or WD Blue. WD Green has lower rpm at 5400rpm, meaning it will be slower than the first 2 drives (which have 7200rpm).
For PSU, can try bargainin to get it at $125 bundle price at Tradepac.