Help me "finish" building my PC : )

Please?

Around Christmas I got the easy stuff. Couple of 750GB hard drives, power supply, case, windows vista.

I now need the more difficult and confusing (to me) components.

For processor I have settled on a Q9450. I was waiting for this before I finished the machine. It's out... time to finish it.

For a motherboard I have settled on one with a 780i chipset. I want SLI support and Q9450 support right out of the box, so I am assuming this is the best choice? I don't plan to go wild with overclocking, but having some options would be nice.

For graphics I have settled on an 8800 GTX (with the possibility of a second at some point.) I REALLY was hoping for a new NVIDIA card by now but it looks like the new cards aren't so hot... at least not at 1080p resolution.

For memory, I'm confused. Do I *need* to get DDR3? Can I get DDR2? If I get DDR2 what speed do I need to get? (I'm lumping this in the motherboard section rather than make 2 posts... I figure someone here will know : ) I want to get 8GB, and I can pick up some OCZ PC1000 DDR 2 memory for much cheaper than I can get DDR3 for... so if I can get away with that I'd prefer it.

Sound card will be a Creative X-Fi if I buy one, or I'll just use one of the old SB Live series cards I have for now until they get their drivers straight.

That sound alright to finish this system off? I have around $1200 set aside to finish it and this brings it in just around that point I think. Any suggestions for changes, or answers to questions are welcome and appreciated. Thanks!

Yeah I just was poking around prices on the 8800gts cards and it looks like I have the following choices :

8800 GTX for $340 -$50 mail in so $290

2X 8800 GTS for $230 each -$30 mail in each or $400 total


or as you suggested the 1GB 8800GTS (I had no idea the 8800GTS came in over 512MB versions?) for $370


Given the options above, what would you go for with graphics? All fall within my budget so they can all be considered the same price as far as I'm concerned.

This will be hooked up with a 1080p 42" panasonic plasma. I'd like to be able to run everything at 1080p resolution, and assume the 512mb cards may limit me (even if they provide the best performance at lower resolutions in SLI).