You beat me to it. Good choice on the RAM since you wont need to mess with the Voltages.
Ok with a $700 budget this is what I recommend:
P35-DS3L ($83) or P45-DS3R (To do CrossFire on a budget, $125)
Q6600 (for video editing, etc, $180) or E8400 (gaming, $170)
WD 640GB AAKS ($85)
ATI 4850 ($165)
XIGMATEK S1283 ($27, after MIR) + bolt in kit ($7) [ONLY if OCing]
G.Skill 4GB DDR2 800 RAM $80 ( http://www.newegg.com/Product/Product.aspx?Item=N82E16820231122
Corsair 650TX ($90 after MIR) or PC Power & Cooling 610 ($80 after MIR)
Any DVD RW and case you want.
Total (with P35-DS3L, Q6600,PP&C 610, and every thing else excluding case/DVD RW)= $541