amd 64 i would get, as of the mobos, im not to shur. I know asus makes good allround amd mobos. But if ur gona be gaming, and a lil not advance ps, go with amd.
As koldapu said, sata is worth it if ur budget is 1400$ smaller cables, and faster to open files and stuff.
frys is the best store, but try to stick to online sites, koldapu got the best ones there. u might wana check www.pricewatch.com
to c how the prices compare to other ssites and all.