more computer help for fr3nzy...please
 

This will be my 3rd build, my first two were for friends and I got a good amount of practice in the classes offered at school. I've been looking to make myself a computer for a while and I have about 750 dollars to spend, tax not included. (going to take a shot at OCing) I already have myself a monitor, keyboard/mouse, and speakers. I don't need some fancy sound card (integrated will do) and I'd like to be able to run games on the level of HL2.

I'm not coming here to say what I want and have you guys come up with perfect-fitting miracle parts, but I would like suggestions or tips/pointers on OCing and what parts would probably fit my needs within my price range. I'm willing to buy AGP or PCI-E, I don't mind either, but I'd like some degree of upgradeability (I don't know if that's even a word).

Any and all suggestions are welcome, thanks again in advance guys.