Overclockers Uk normally do excellent deals and have £20ish insured next day delivery. Ordered the most expensive parts for my rig from there. Came the next day 8 hours later, in what was indestructible packaging. I had to use a lock knife to open the outer box it was that well wrapped.
" Titan Xeon "
Looks pretty good what what you want and its in your price range. Upgrade the Gpu to a GTX 460 and your done. 4Gb of ram is plenty. You'd only really need more Ram when zbrush upgrades to 64bit compatability since nothing else would really use 8Gb. Im running 13gb and with max rendering at full out stupid highres images it scathes 5gb's
Heres one of the 50 5 star reviews.
Quote: "Been wanting a relatively high-spec PC for long time.
After reading all 50 5-Star reviews I can still barely say that the system exceeds my expectations.
Starcraft 2:
Ultra settings - Frame rate capped at 60 and develops no noticeable spikes in a 2v2 with all armies maxxed. Ultra is too shiny and I play with shaders turned down, I have no doubt this could handle 4v4.
CoD 4+Black ops: Everything on, framerate capped to 100 (because anything more is needless?) Runs smooth as anything, no problem catching 5 kills from a flank.
Dragon Age

rigins :What can I say, it just looks beautiful, however max settings make their armor weirdly shiny.
Counter-Strike: Source
This I haven't tweaked around with so much as there's a lot of settings to deal with but from what I've seen it also handles this beautifully.
I don't really have anything much more demanding. Everything I've seen it do it has done so FAST!
Had a blue screen on the first day, has not reoccurred. Confidence in OC Support."