Advice to Build my Computer

Hello everybody i was thinking to get the ASUS P7P55D LGA 1156 Intel P55 ATX Intel Motherboard and them i take a look in to the GIGABYTE GA-P55-UD4P LGA 1156, i don't go to to SLI or Crossfire, witch one you guys think have more performance or witch one is more worthy for the money and performance? and witch case you guys think is better the

GIGABYTE: http://www.newegg.com/Product/Product.aspx?Item=N82E168...

ASUS: http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Witch Case....

COOLER MASTER HAF 922 RC-922M-KKN1-GP

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

or COOLER MASTER Storm Sniper SGC-6000-KXN1-GP


http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Memory:

4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 2000 (PC3 16000) Desktop Memory Model F3-16000CL9D-4GBRH

Kingston HyperX 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 2000 (PC3 16000) Desktop Memory Model KHX2000C9D3T1K2/4GX

G.SKILL Trident 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 2000 (PC3 16000) Desktop Memory Model F3-16000CL9D-4GBTD

Kingston HyperX 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 2000 (PC3 16000) Desktop Memory Model KHX2000C8D3T1K2/4GX

Patriot Viper II Sector 5 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 2000 (PC3 16000) Desktop Memory w/ 3DMark Vantage Model PVV34G2000LLKB

If any body have a good suggestion of ddr3 4gb 2x2 kit under the 160 bucks i gonna love it

another thing is the PSU.... I lookup the Corsair HX850W and Corsair HX750W I go to buy the new 860 i7 (1156) a EVGA GTX 260 Super clocked video card (single card) 2x2gb ddr3, high End mother, etc. and I want to know if the 750 its gonna be good enough, i found the 750 for $135.99 after mail-in-rebate and the 850 @ $169.99 both of them @ zipzoomfly, so its anybody can give me a hand, i Dont know what to buy for the money and the performance.... I really go to appreciate that

thks for your time guys!!!