If you can wait for the prices to drop - do so. I believe that the x2 3800+ is on the list to drop significantly. I also have that CPU, and it is great. I have it OC'd to 2400MHz (x2 4800 speed, though not all the specs).
I am currently using an EVGA 7600GT that I also OC'd (FEAR FPS = 50-70 @ high settings; HL2 FPS = 80-100 @ high settings). If you have the cash, check out the 7900 series.
As for RAM, Corsair and Patriot are both good choices. Corsair's website will provide recommendations based on your relevant hardware and intended use (OC..?)
You might want to reconsider the SLI MoBo. I feel silly having purchased my ASUS SLI board, I could have saved some money... learn from my folly.
Hope this helps. Keep us posted as to what you decide.
[SIZE=\"1\"]E6400 @ 3.4 , Noctua 120
7900GT @ 670/1680 , VF900
2 x 1GB Patriot 6400 @ 425
WD SATA 250GB
Neo HE 550
P180 / G15 / MX1000[/SIZE]