Need help selecting mobo and memory combo

I'm planning a new i7 build. I will probably do it as soon as I can make up my mind about all the components. I'd like to do it in the next few days in light of MicroCenter's $200 i7 special.

I'm looking at combo deals on Newegg. I'm looking at both Asus P6T and P6T Deluxe V2 mobos. I'm also looking at RAM anywhere from Corsair Dominator (6GB) down to Corsair XMS3 1333 (6B).

I can get the following for the following prices:

P6T Deluxe mobo with 6GB Dominator DDR3 1600 RAM - $430

P6T Deluxe mobo with 6GB XMS3 DDR3 1600 - $410

P6T Deluxe mobo with 6 GB XMS3 DDR3 1333 - $400

P6T mobo with 6GB Dominator DDR3 1600 - $385

P6T mobo with 6GB XMS3 DDR3 1600 - $365

P6T mobo with 6GB XMS3 DDR3 1333 - $355

Those are the combos I'm basically looking at. The P6T board scares me a little bit because the PCIe X16 slots will leave no room between two dual slot graphics cards running in SLI (which I will do down the road). One of the main reasons I'm building a new computer is because I'm battling serious heat issues right now (hardware is just getting old), and I don't want to build a new one to have the same problem. I'll be doing gaming at 1920X1080 (have a GTX 275). I read in the RAM shootout here on THG that 1600 RAM is a bit overrated right now in comparison to 1333. What is the big deal about Dominator RAM?

I guess I would just like some opinion considering those price points which the best deal might be. I've got all other components selected. I just need to decide on one of the 6 above. Thanks.