For a $1200 gaming build, I could also recommend your graphics if you want. You could probably afford Radeon 7950 Crossfire and if not, then Radeon 7870 Crossfire or a Radeon 7970 GHz Edition. I don't know if you've heard of it, but here's a great site that might help you: http://pcpartpicker.com
It doesn't show combo deals, but for picking individual parts, it's great.
650W is almost overkill for that build. A 750W would be overkill unless you wanted to throw in a second 7950, in which case an 850W might be better anyway.
What's wrong with small form factors? SSDs are intended to be able to fit in both desktops and laptops ideally, so they're made in 2.5" form factors most often and the performance advantage over hard drives is generally huge.