My 1st build nVIDIA/AMD....REQ opinions and guidance

Hello,

I would just like some opinions on my 1st build and which way I should be going next with it. Should I bother upgrading the RAM? What should I be doing to squeeze more gfx power out of my current setup? I am planning on a RAID setup, most likely only 2 more drives. I am also considering a blu ray drive, possibly a burner. Used mainly for gaming/media. I may begin using 3d and 2d design utils and/or audio composition utils.

CPU
AMD Phenom II X4 920 OC'd @ 3.08Ghz (41°C idle 56 under load, Tt SpinQ CPU cooler))

Mobo
Asus M3N-HT Deluxe/HDMI
-nForce 780a SLI chipset
-PCIe 2.0 x3 (fully populated all 3 run @ 8x....2 @ 16x)

RAM
2x2GB 800Mhz OCZ DDR2 (stock timing & voltage, mobo supports up to 8GB@1066Mhz natively)

Drives
-HDD
Hitachi 500GB 7200 RPM SATA
-Optical
LITE-ON 24x DVD burner

OS
Vista64 Home Premium


GFX
BFG 9800 GT OC+ 512Mb(factory OC'd, 54°C idle 68 under load)
-SLI'd with
BFG 9800 GT 512Mb (not OC'd....should I? 45°C idle 54 under load)


PSU
KingWin 800w (modular with only 2 PCIe 6/8pin modules)

Case
CoolerMaster HAF 922 (9 fans total on/in case)