hi there, thanks for the enquiry....
i have put together a custom built machine, based on your budget...
PC hardware Specs
case - antec nine hundred
psu - antec tp650
motherboard - abit ip35 pro
cpu - intel q6600
heatsink - zalman 9700
memory - 2gb corsair ddr2 800 c4
hdd - 500gb samsung sataII
dvdrw - pioneer dvdrw
graphics - geforce 8800gts 768mb
cost of parts - £935
optinal / additional costs
windows vista home prem 32bit - £69
build cost - £50
19" tft asus - £118
this spec machine would do you fine for gaming...if you did want something with a bit of upgradablity then you could swap the board for the asus p5n32e-sli (extra £10) this would enable you to upgrade to an sli set using 2 graphics cards - but to do this you would also need to upgrade your psu to a 850w (approx + £80)
hope this all makes sense !!!
if not please let us know, and we will try to help you out...
thanks
mark
www.yoyotech.co.uk