It seems that you have done your research well...
As for the parts,..
1. Casing - The Antec 900 is a very good case but I dont think it would be a Quiet one...
Here is a good option if you want to take into the noise factor into account...
This case also has very good airflow...1 x 120mm front fan,1 x 140mm rear fan, 1 x 230mm top fan
Thermaltake ElementS
http://www.newegg.com/Product/Prod [...] 6811133077
2. CPU - No doubt the i7 920 is the better option...Make sure you get the D0 stepping and it will happily overclock as good as the i7 950.
But instead of that CPU cooler, the Xig Dark Kinght or the Scythe Mugen 2 would be better for the i7 overclock...
3. I would vote for the intel 80GB SSD...You can identify them by 1) Color - They are silver colored whereas the G1 are Black colored. 2) Model number - Gen 1 - SSDSA2MH080G1 Gen 2 - SSDSA2MH080G2 Notice the G1 and G2 at the end ???
Maybe its better to wait till they restock them and then make the purchase...
4. For data drives, 2x WD Black 640GB in RAID 0 would be a very good option.
5. Backup drives are fine...
6. The GTS 250 is a good option for you usage and is actually a overkill but still it would last you long...Get the 1GB version as extra memory would help...
7. RAM - If you can get lower timing on the RAM...
http://www.newegg.com/Product/Prod [...] 6820226036
8. PSU - You can go for a modular PSUs as you can get rid of unwanted cables from the PSU...
SILVERSTONE ST60F 600W ATX12V / EPS12V SLI Ready CrossFire Certified 80 PLUS BRONZE Certified Modular Active PFC Power Supply
http://www.newegg.com/Product/Prod [...] 6817163109
or
CORSAIR CMPSU-520HX 520W
http://www.newegg.com/Product/Prod [...] 6817139001
Anything above these PSU is just an overkill for your configuration...These PSU can handle upto GTX 285...