Mobo: Gigabyte GA-P55M-UD4
Best budget 1156 board out there in my opinion. Supports x8x8 cf, Gigabyte quality. Only downside is the matx factor, but 1156's lack of northbridge negates alot of the heat issues that other chipsets have. I looked very hard at this board.
RAM: G.Skill 2x2GB Ripjaws 9-9-9-24-2T 1600
Not exactly performance champs, but the price is right and G.Skill has made a name for itself in quality. I really wouldn't worry much about the speed, it's been shown pretty conclusively that the performance benefits of topshelf ram vs slower less expensive ram is negated to all but benchmarks.
Don't bother with the P7P55D LE. It's quite misleading as newegg has it listed as CrossfireX support. What they're referring to is a single pcb with dual gpus (ie 5970) This board only supports a single x16 card. The second mechanical x16 is rated at x4 electrical speeds.
So this comes to $299 before taxes/shipping, which would put you a bit over $300. The PRO is a great board and has all the features you need. There is probably cheaper RAM out there, but G.SKILL is a great company and these are good sticks of RAM. If you can affort the extra $30 (or so) then definitely go for this.
Went ahead and got the p7p55D-E PRO and went with CORSAIR DOMINATOR 4GB DDR3 PC10666 1333MHZ memory actually got it as a combo with the i5-750 seeing as I hadn't actually bought the CPU yet so I got them fairly cheap.