New build - Need advice on PSU and GFX card

Here's my proposed set-up. Please check and see if everything is compatible and happy.

Approximate Purchase Date: Before February
Budget Range: <1000 After rebates
System Usage from Most to Least Important: Light gaming, internet
Parts Not Required: Keyboard, mouse, speakers, OS
Preferred Website(s) for Parts: Reputable websites / in-store is fine
Country of Origin: USA
Parts Preferences: No preference
Overclocking: No
SLI or Crossfire: No
Monitor Resolution: 1920 x 1080

Motherboard
GIGABYTE GA-P55A-UD3 LGA 1156 Intel P55 SATA 6Gb/s USB 3.0 ATX Intel Motherboard
http://www.newegg.com/Product/Prod [...] 6813128412

Processor: Core i7-870

GPU
Either
XFX HD-577A-ZNFC Radeon HD 5770 (Juniper XT) 1GB 128-bit GDDR5 PCI Express 2.0 x16 HDCP Ready CrossFireX Support Video Card
http://www.newegg.com/Product/Prod [...] -_-Product

or

EVGA 01G-P3-1366-TR GeForce GTX 460 SE (Fermi) 1GB 256-bit GDDR5 PCI Express 2.0 x16 HDCP Ready SLI Support Video Card
http://www.newegg.com/Product/Prod [...] 6814130591

RAM
CORSAIR XMS3 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model
http://www.newegg.com/Product/Prod [...] 6820145260

HDD
Western Digital 1 TB Caviar Blue SATA 7200 RPM 32 MB Cache Bulk/OEM Desktop Hard Drive WD10EALS
http://www.amazon.com/Western-Digi [...] 610&sr=1-1

Optical Drive
ASUS Black 24X DVD+R 8X DVD+RW 12X DVD+R DL 24X DVD-R 6X DVD-RW 12X DVD-RAM 16X DVD-ROM 48X CD-R 32X CD-RW 48X CD-ROM 2MB Cache SATA 24X DVD Burner - Bulk - OEM
http://www.newegg.com/Product/Prod [...] 6827135204

Case
Antec Three Hundred Black Steel ATX Mid Tower Computer Case
http://www.newegg.com/Product/Prod [...] -_-Product

PSU
CORSAIR CMPSU-650TX 650W ATX12V / EPS12V SLI Ready CrossFire Ready 80 PLUS Certified Active PFC Compatible with Core i7 Power Supply
http://www.newegg.com/Product/Prod [...] 6817139005

Questions:
- What voltage PSU do I need?
- Which graphics card would be better? 5770 for $130 or GTX 460 for $150?
- Should I get 8 GB of RAM?
- The only difference between the Antec 300 and Antec 300 Illusion are the two additional fans (plus lights) in the front. Are the two fans necessary?

Thanks for your help.

I'd opt for the 460, a very solid midrange card....

if pondering SLI in the future, get at least a name brand 750 watt PSU..

@mdd1963: Yeah I was opting towards the 460 as well. I probably won't go for SLI.

@banthracis: I'm not looking to get the top of the line components. I think my current set-up will be more than enough for what I'm looking to do. Do you think I should wait for Sandy Bridge to come out before buying my parts? Do you have any advice for PSU?