Hi people!

I'm about to build myself a new computer. After spending all my life waiting for Windows to load I finally got a Macbook a couple of years back. However, now it's time to get a new system but this time I want a whole lot more power in it. The problem is that I don't want to go back to Windows and I don't want to spend all the money needed to get a good Mac.

I've been checking for parts online and found following setup:
CPU Intel Core i7 920 2,66GHz Box
Motherboard Asus P6T Deluxe V2 (supports SLI/CrossfireX, >24GB DDR3 RAM, 6xSATA2)
RAM Corsair XMS3 Twin3X 3X2GB DDR3 PC12800/1600MHz CL9
Graphic card Sapphire Radeon HD4870 Vapor-X HDMI 2GB
Hard drive Samsung SpinPoint F1 HD642JJ 16MB 640GB

Will this system work for running MacOSX? I might get another graphics card later on to run SLI, will it still work then?

Thanks for feedback!