[3.0charlie]

I've built a cart for 1383$, with the Haf X and a 6950 2Gb GPU.

Replace the Z68 for the P8P67 LE. I've used that board and clocked a 2600k to 5.0Ghz. Solid board. And since you want a GPU, no need for the Z68's onboard GPU.
Replace the X750w with the X650w. Plenty powerful.

You'll meet your budget.