I would disagree on the CM 690II. Granted, I purchased the case for $40 more than what it is now, but there are several minor design flaws (e.g. the cutout in the backplate is a little too high, making it almost ineffective) that add up to a frustrating case.
You've got the 920. Check.
Get a decent CPU cooler. You get the benefit of turbo boost, or the ability to OC. I like the Corsair HD50 ($70) [NOTE: the HD70 just came out, but it's $50 more]
I like the mobo Wiked recommended ($220)
You need to see if the RAM you have is worth using. If yes, then get enough to utilize tri-channel (using 3 of the slots).
Though the HAF 922 has some issues, it doesn't have as many as the CM690II and it is the same price ($80) [personally, I like the style better, too]
The Corsair PSU is an excellent choice ($139)
While the 480 is a top-notch card, the 470 is a better value (about $200 cheaper)...or 2 460s in SLI would cost less than the 480 and give you slightly better performance. Right now, I'd say the 470 ($270)
When you say drives, I think you mean DVD drives, but not sure if you mean HDDs. Samsung Spinpoint F3 1TB should cost no more than $70.
That's $850. Still need to figure out RAM, but now you can get a 24" monitor or 60GB SSD (both really) and still be under the $1500.
Hope this helps.