I would stay in the 128GB - 256GB range for the OS SSD and maybe bump the HDD to 1.5TB or 2TB.
As for a PSU....I'd say at least 650w from a good manufacturer as a bare minimum and 750w - 850w would probably be better. Seasonic makes some of the best units out there but you're going to pay for the quality. Antec used to make some good units but they're hit or miss lately. Enermax might be one to check out as well. Power supplies aren't an area you want to skimp out on, so do some research on any potential candidates before you purchase on.
Everything else looks fine and if you're wanting to be a little more budget-minded rather than "premium enthusiast", try this video card out.....
PNY VCGGTX670XPB GeForce GTX 670
Yeah, it's still a little expensive, but it's $150 less than the GTX 680 but it will still do quite well. I'm using the previous generation, a GTX 570, and alongside my 8GB RAM and i5-2550k, I can run either High or Ultra settings on all my games. Battlefield 3 on Ultra runs fairly well but I'd rather have slightly higher FPS and a little less eeye-candy so I run that on High.--
I'll be stretching out the rhyme like gravity stretches time.