Power Supply: Corsair Gaming 600W 80 PLUS Certified ATX12V Power Supply ($67.34 @ TigerDirect)
Optical Drive: Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer ($19.98 @ Outlet PC)
I wanted to choose my own parts so I could learn what I was doing, not just copy someone else's work. Also, my budget is in the area of $800, but I am flexible, so if you have any suggestions on changes please let me know.
http://www.anandtech.com/bench/CPU/2 - this site does a great job allowing you to compare to different CPUs together across several benchmarks. You can look at the core i5 vs core i7. From what I've been reading, you may be better off getting an i7. But like I said, compare the specs first and see what works for you!
Microcenter has the core i5 you are looking at for $189 and $50 off a motherboard. I shop there all the time (there is one down the street) and they are good with shipping also.
This is actually the unlocked version (for overclocking) cheaper than what you have posted ...
MicroCenter does have some great deals on the i5-3570K but those are for in store pick-up only. If they aren't too far from you it might be worth it. I think 8GB is good there isn't that much of a increase in performance compared to the increased cost. The 560 is old get the 660 with the money you save from the RAM its a smart buy. I didn't see a O/S on your list but I'd use Windows 7 Home 64bit, unless your logging into a domain you don't need Pro.