I think its a better idea to match the AMD cpu with an ATI chipset as the others have suggested, but you can only crossfire with that, not SLI.
For a crossfire setup, go with a 890GX or 890FX motherboard.
Sweet Case. I'd buy it if I didn't get the Antec on a discount.
Even though I say I'm willing to spend more on the mobo, I only bought the parts when they're on sale.
The Corsair PSU I'm using's got pretty good reviews. Do you think I need something better?
I live in Seattle too and I havn't noticed anything too drastic.
Are Avexir RAM really that bad? It's a new company, and it's made in China, but the reviews so far are decent.
The Corsair PSU certainly is a good one, I prefer modular cables myself but many folks swear by the Corsair PSU's.
I would say the Avexir is a brand I would not recommend because I never heard of it before. Corsair is a solid brand, I like OCZ, but most guys have a favorite over time because that brand has given them the least trouble. If it works for you, then its good ram.
Yes, the motherboard is AM3 and it will work with the X4 965.
Don't worry about the 790GX result, As long as the mobo is not ,limited to 95Watt CPU's and is AM3 you will be fine. Another stipulation, am2+ mobos can sometimes run AM3 CPU's but will only utilize DDR2 memory.
The X4 965 will work with 890 series motherboards. In fact, you could choose a 790GX mobo if you wished to save money. However it is possible that the board would not work with your CPU unless you had another CPU to update the BIOS.
890gx or fx will be your best choice for a new build with that CPU, or of course the nVidia 980a for SLI.