Originally Posted by WolfShade
If you go the "build-it-yourself" route, make sure that you have a fast enough CPU, PLENTY of RAM (at least 6 Gig; 8 or more is better), and that the video card you purchase will be fully compatible with the chipset of the motherboard that you purchase. I've seen some issues due to a video card (that will mostly work) not being fully compatible with a motherboards chipset. The game would be smooth until there was a lot of fast-paced rendering, then suddenly the game would just crash.
Sorted it now, brought one from ebay, custom built, cost me £900.