Well i would say 2*400 rigs .stuff like hard drives and optical drives and sometimes cases you can reuse so what i would do is build your first rig and get decent HD's and optical drives then when you come to upgrade you already have decent hard drives and optical drives so all you need is a psu,mobo,cpu,ram and gpu for your next computer .
Then sell all the current mobo cpu etc and you may find the new rig costs less
im american, so i don't know how the £ system works.... but... i believe a £ is about 2 times as much as a american $. so, i think the £800 system would be better...
umm id have to disagree with you on that $800 or £400 would get you a half decent computer nothing brilliant but it would do most jobs and play most games IMO
My PC I'm ordering will cost me about £900 with a good monitor.
That includes a Antec 900, quad core, 2GB's RAM, 8800GTS 320MB, and 2 320GB HDDs.
Its possible to build a good one for £800 if you didn't have to buy a monitor/case too.
umm id have to disagree with you on that $800 or £400 would get you a half decent computer nothing brilliant but it would do most jobs and play most games IMO