My PC Configuration

-Intel Core 2 Duo E8500 3.16GHz ,6MB L2 Cache ,1333MHz FSB, LGA775, 45nm (w/ Stock CPU Fan and Heatsink)
-Cooler Master RealPower 650W SLi PSU
-Asus Striker Extreme 3 Way SLi LGA775 (nFORCE 680i SLi Chipset)
-8GB PC2-8000 DDR2 (4x 2GB)
-2x Visiontek Radeon HD 4870 1GB GDDR5 PCIe 2.0 + MSI Radeon HD 4850 512MB GDDR3 PCIe 2.0 = CrossfireX 4870 + 4870 + 4850
-Asus SupremeFX II 7.1 HD PCIe Sound Card
-D-Link 56K V.92 PCI Modem
-Geniatech ATSC HDTV PCI Tuner
-External Dual Layer DVD Burner
-2TB S-ATA HDD (4x 500GB S-ATA)
-500GB Ultra ATA HDD

Accesories:
-Logitech MX3200 Wireless Laser Keyboard w/ LCD
-Logitech MX Revolution Wireless Laser Mouse
-Logitech X-540 5.1 Channel Surround Sound Speakers
-Generic USB 2.0 Web Camera w/ Built-in Microphone
-17" LCD Monitor (1440x900@75Hz)
-Canon iP1800 Photo Printer


Note:
1.Can I CrossFireX both the 4870 and the 4850
2.Can I have 4x 500GB HDD combined and make 2TB
3.I don't have a PC Case yet.

1. Only X58 can run either CF/SLI out of the box. 680i can't. All other chipsets can't.

You could pick up a HD 4870X2 for now and wait for nvidia's next gpu. IMO, for 1440x900, HD4850 alone is enough. If you want to max out the games at native res, HD4870 or X2.

2. Yes, but they will be separate drives startin from C:.

yeah that will play any game.

auscanzukus is correct. Crossfireing 2 ati cards won't work with a Nvidia motherboard. You need an intel x48 chipset.

1. Pick a mobo with X48 chipset. You can run 2 cards in crossfire, so take the 2 4870 even it's too much poerful for this resolution. Upgrade your monitor to a 24" to take full advantge of your PC.

2. Yes, you can use a RAID0 config if you want but make backup on the other hard drive...

3. Maybe a antec twelve hundred...

The power supply isn't the best for a such a setup. Change it for a Corsair 750W http://www.newegg.com/Product/Prod [...] 6817139006. Good deal.

Do you only have dial up internet connection? If so you probably will not be able to play any of those games on line. 8GB of ram is way overkill. The motherboard that you have selected is an Nvidia based board but you have ATI video cards selected. You may want to pick a different motherboard or change to Nvidia cards. 3 Video cards is also a wast of money if you are only going to run 1440 x 900 res. one card would be more than enough.

To your notes:
1. I would just get one 4870x2 instead of 3 cards http://www.newegg.com/Product/Prod [...] 6814102768

2. Yes you could raid or stripe them together to do that

3. do your self a favor if you have room where you are going to
put your case and get a full size case like these.
http://www.newegg.com/Product/Prod [...] 6811119138
http://www.newegg.com/Product/Prod [...] 6811119103
I have both of these cases and they kick ass!