Almost done, please help me finish!~

Rosewill RP600V2-S-SL 600W ATX12V v2.01 SLI Ready Power Supply - Retail $64.99

[url] http://www.newegg.com/Product/Prod [...] 6817182032[/url]

ASUS P5Q PRO P45 Motherboard $139.99

http://www.newegg.com/Product/Prod [...] 6813131299

Intel Core 2 Quad Q6600 Kentsfield 2.4GHz 2 x 4MB L2 Cache LGA 775 Quad-Core Processor - Retail $189.99

http://www.newegg.com/Product/Prod [...] 6819115017

EVGA 512-P3-N801-AR GeForce 8800 GT 512MB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready SLI Supported Video Card - Retail $149.99

http://www.newegg.com/Product/Prod [...] 6814130318

CORSAIR 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory - Retail $57.00

http://www.newegg.com/Product/Prod [...] 6820145184

Western Digital Caviar SE16 WD6400AAKS 640GB 7200 RPM 16MB Cache SATA 3.0Gb/s Hard Drive - OEM $84.99

http://www.newegg.com/Product/Prod [...] 6822136218

Those are what I have chosen.
1) Is everything there compatible?
2) What OS should I get? Someone told me to get Windows Vista Ultimate 64 bit but I heard Windows Vista slows down the computer and hogs a lot of resources..?
3) Can someone help me choose the disc drive? I want to be able to install and play the newest games. Play Dvds and CDs and burn.
4)Can someone help me choose a case? I would like the cheapest one possible that suits what I have.

Note: I plan to play COD4, TF2, Crysis, FEAR 2 and other new games. I also plan to overclock the cpu to at least 3.00 ghz.

I am not sure what else I need. Please help me finish up my computer system.
Thanks a lot!

No to that PSU. There was a Rosewill (500-RP iirc) that surprised one of the guys at jonnyguru by passing all their tests, but the brand as a whole is considered crap. For that price, you can find something much better by Antec or OCZ; a little more will get you Corsair or PC Power & Cooling.
No to the RAM also. For $63, you can get this Mushkin that has better timings and runs at the JEDEC standard 1.8V: http://www.newegg.com/Product/Prod [...] 6820146731
If budget is a concern, then this Mushkin for only $50 AR has slightly looser timings but also runs at 1.8V: http://www.newegg.com/Product/Prod [...] 6820146692
For that degree of overclocking, you will want a better cooler. Check out this link: http://www.frostytech.com/top5heatsinks.cfm.
If you can afford it, you'll get better performance from an ATI HD4850, but on a budget the 8800GT is not a bad choice.
Good HDD, and P45 is probably the right choice also.
Hard to pass up a good quad, but you might want to consider an e8400 also.
Most any Retail SATA burner would be fine. The Retail versions include software, which you will want.
The cheap ($25) Rosewill cases have room for all that, and can take front and rear 120mm fans, so their cooling is also enough. For another $10-$20, the low-end CoolerMaster cases are a little nicer, and are tool-free, but inside arrangement is similar. I've used both, and would buy either again. If you're going to move or ship the system, the tool-free mounting of the CoolerMaster should be supplemented with screws to avoid anything coming loose inside.

Excellent advice there from Emp, I second it 100%.