I think you are going over kill on that MB. Unless you intend to run a Tri-SLI setup (which would require 3 nearly identical top end cards), I probably wouldn't bother with it. I remember reading somewhere about the chipset getting really hot on that MB due to a poor design on how the heatsink seats on the north bridge. Maybe they have fixed this ...

My recomendation would something along the lines of
GIGABYTE GA-EP45-UD3R LGA 775 Intel P45 ATX Intel Motherboard - Retail
Or a similiar Asus or even MSI. Usually these are stable boards.

Something else I would suggest is 1066MHz memory (PC2-8500) instead of what you have. Although there have been good reviews about G.Skill I probably would suggest one of the brands that have been around for longer such as OCZ, Crucial, Corsair
I have been using the following and I have been quite happy:
OCZ Reaper HPC 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500) Dual Channel Kit Desktop Memory - Retail


One last point, which doesn't matter as much as the two above, I am not quite sold on the Ultimate version of windows - there is a premium for a couple features that most folks are unlikely to use. The Home Premium 64 bit will be fine and save you a few bucks.