hard question to answer! you will need a high end PC, i think you know what i mean. how much money do you have to spend. £800 for just the computer should do you.
Something with a newer video card, and a fair amount of RAM should do. Maybe like a Radeon 9800 PRO, with 512MB of RAM on a 3.0Ghz processor. That would run well enough for a couple of years.