Alright, so here's what I got
Case - Anything will do, just the things to look for are mainly airflow and size (big enough for your board [ATX form factor is mostly everything] and small enough for the space you are going to be putting it in.) I am a fan of Cooler Master so if you find one of those go for it.
PSU - Pay attention to the required wattage of each of your parts, from the sounds of it you'll need quite a bit of power. I would avoid cheesy sounding brands like LIGHTNING XTREME POWAH; stick to Antec, Cooler Master, or Corsair or another brand you recognize.
Motherboard - With motherboards, it's usually just a matter of quantity: make sure it has all the PCIe and RAM slots you'll be needing, and pay attention to the socket type (most online stores will mention which processor lines are compatible)
RAM: I've had good luck with Corsair, but I've had good luck with generics also. Again check out compatibility with your motherboard. As far as quantity goes, 6-8 GB will be plenty and sounds like will fit your budget.
Processor: Sounds like your i7 is all picked out. If price becomes an issue, though, AMD's Phenom II quad- or 6x- line are beastly for the value. This should come with everything you need to install it, including the fan.
Disc drive: I usually just find one lying around the house. But if it's in the budget, Blu Ray drives can be hand for under $100 regularly on Newegg and such sites.
HDD: Brand is important here. Stick to name brand, no less than 7200 RPM. Looking at your budget, I'd go for 2 terabytes, shouldn't set you back more than $80 USD. Most everything should be SATA nowadays, but check to be sure.
Video card: That 6950 looks like a great value; I'd stick with that or equivalent.
As far as sound card goes, the integrated one on your mobo should suffice unless you're an audiophile. Monitor/keyboard/mouse is pretty much up to taste and price, of course. Let me know if there is anything else you need help with.