PSU: Corsair HX 520W
520 is more than enough, great PSU, and modular to boot. Save you a 10er there
MoBo: Gigabyte P35-DS3L
or even the -DS3R
are great choices. I wouldn't recommend combined DDR2-DDR3 (no real reason for this, just why pay more/ risk more problems for something you don't need). I have a P5K deluxe, which is a great board, but the standard P5k
, I have no experience of. The Gigabytes come highly recommended on these forums, and many have experience with them. Get the DS3R if you want a RAID array (I wouldn't recommend)
If you're really on a tight budget, you could save a lot on the case as well
EDIT: I've only used overclockers, and had a successful RMA with them. 1 order with scan that went fine, but can't vouch for them. You'll read bad reviews for everywhere. Just check the price of the same order at a variety of places.