I7 870 w/P55 vs i7 920 w/X58

I have reached that deciding point in my build where I need to decide whether or not to go with socket 1366 or 1156. I don't plan on doing much overclocking of my system at this point. I'm looking for solid reliability and out of the box performance. I will only be using the single GTX 295 card so having multiple PCI-E X16 slots is not a concern. I am using an Antec P183 case which supports the CPX power supply I have selected. Here are the two builds I have put together right now...


Socket LGA 1156 Build:
Intel Core i7-860 Lynnfield 2.8GHz LGA 1156 95W Quad-Core Processor Model BX80605I7860
GIGABYTE GA-P55-UD4P LGA 1156 Intel P55 ATX Intel Motherboard
Antec CP-850 850W Continuous Power CPX SLI Certified CrossFire Ready 80 PLUS Certified Modular Active PFC
Mushkin Enhanced Blackline 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666) Dual Channel Kit Desktop Memory Model 996652

Total cost: $694.96


Socket LGA 1366 Build:
Intel Core i7-920 Bloomfield 2.66GHz LGA 1366 130W Quad-Core Processor Model BX80601920
EVGA 141-BL-E757-TR LGA 1366 Intel X58 ATX X58 SLI LE Intel Motherboard
Antec CP-850 850W Continuous Power CPX SLI Certified CrossFire Ready 80 PLUS Certified Modular Active PFC
CORSAIR XMS3 6GB (3 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Triple Channel Kit Desktop Memory Model TR3X6G1600C9

Total cost: $803.96


As you can see there is a $100 difference in favor of the 1156-build over the 1366-build. However, the 1366-build has 6GB's of triple channel 1600 RAM as opposed to the 1156-build's 4GB of dual channel 1333 RAM. Of course the 1156-build also has a 140MHz advantage over the 1366-build in processor speed as well as turbo boost to assist it in applications which can't make use of all 4 cores.

Which of these two builds would you go with or what would you change?