New system build... need some input!

So I'm moving out and decided to donate my old comp to a friend so he can actually play games with me online. Now I find myself without a computer and had to borrow my brothers... Not fun.

Luckily, I can build a new system for myself and put it in the business as an expense so my budget is basically whatever I "need/want!"

So... here's a little background info...

I play a lot of different games (Crysis, Bioshock, TF2, COD4, etc) and currently play on a 24" 1920x1200 resolution monitor, with a second output going to a large LCD 1920 x 1080 tv.

I've built about 10 systems over the past few years for myeslf and friends am experienced with overclocking, watercooling, and even a few case mods.

Now my problem is, there are way too many options out there!

What have a decided for sure?

Case:

Either a Coolermaster Cosmos S
http://www.newegg.com/Product/Prod [...] 6811119150

Or Coolermaster Stacker 830
http://www.newegg.com/Product/Prod [...] 6811119122

I want DDR3 memory. (Is the DDR3 2000 kit worth it?)

Either 4GB of
http://www.newegg.com/Product/Prod [...] 6820145190

Or 8GB of
http://www.newegg.com/Product/Prod [...] 6820227297

Power Supply
http://www.newegg.com/Product/Prod [...] 6817814011

Beyond that? It's all up in the air...

Do I want to get a QX9650? or just overclock a Q9450?

Which motherboard to get? Obviously depends on the graphics cards I use!

Graphics cards? If I'm going to get an ATI I want the 4870x2 that's not out yet, so in the meantime should I just buy a 9800Gx2? I can give it to my brother after to use. Or maybe I can buy 2x 4850's and give those to him after (his mobo is a crossfire board)? REALLY not sure what to do! I've even considered getting two GTX280's. This is one area I need some advice!

Hard drives? Two velociraptors in raid 0? or Two 1 TB Samsung F1 drives?

Once I decide on components I can put all this on order! I'll order the case ahead of time because my friend is going to be painting it for me and I may get the inside powder coated.

I'm also doing full water cooling with an air conditioned radiator that I can stick outside in the winter!

Any help will be appreciated!

Thanks

I have the CM Stacker 830 case and it's very good but the side panels are a pain to put back on for some reason.

If you're going to use 2 monitors I would definitely get Sli or Crossfire graphics cards. Get the 2 of the 4870s and Crossfire them or the GTX260/280 and SLi them.

Get 8GB of RAM if you're using a 64bit OS, I have 4GB of RAM and Vista 64bit uses 30-45% of RAM when it's idle.

For the processor, save some money and get the Q9450.

For the HDD I would get 2 velociraptors because 2TB of HD space just seems way overkill to me.

The PSU might be a bit overkill, maybe get like a 1000w(it might not be overkill, that's just what I think)

Case - I'm not sure, but the Cosmos 1000 was a good case so I'm guessing the S only improved on it.

PSU - PC Power and Cooling 750w. 1300w is just overkill.

CPU - Q9540

GPU(s) - Either the two 4850s or two 4770s. SLI DOES NOT support multiple monitors as of yet, where as Crossfire does.

Mobo - Gigabyte GA-X48-DQ6 or if that is too expensive the GA-X48-DS4

HD - I'd go in the middle two Western Digital SE16 Caviar 640GBs in Raid 0. They are fast and quite because the only have 2 platters.