Why do you want cheap PSU for such good components? IMHO it doesn't make sense to spend a lot of money on 8800GTS and then go for cheap PSU. I would recommend Silverstone element 500W Plus for that rig. It's not cheap, but not expensive either, and it's great PSU (very powerful - over 430W on combined 12V rails, stable and very quiet).
Xclio has decent components in their PSUs, but nothing compared to Corsair, Enermax, or Seasonic. They also aren't very well known (I had never heard of them until recently).
If somebody hasn't already told you this, I will.
*Your PSU is the MOST important component in your computer.*
I'd go with a Corsair HX520W from buy.com; $95 shipped I think?
If you want cheap try the Forton (FSP). They seem to be a little more well known. However Xclio and FSP are on the recommended list which can be found here
The PSU is the driving force behind your PC, it does not make sense to cheap out on it if you have good parts. Especially if you want to OC.
I would recommendt he Corsair 520HX, really one of the best PSUs out there. Check around though as Newegg tends to be higher than places like ZipZoomFly on it for some reason.