650 would do you fine for SLI 460s. The PSU you've selected is way overkill; it could handle SLI 580s. Wait, actually, after seeing that low price I think it would possibly die if you loaded it up.
I like the CPU, RAM and HDD (not much variation there), and the case is purely your style preference.
The gigabyte states 16x/8x/4x but when you're running Crossfire, you'll run at 8x.8x the same as the Asrock. Also, it isn't a big deal since even if the Gigabyte did run 16x/8x it would only be a few percent difference. I just suggest the Asrock because you save money.