GPU would be something along the lines of a Radeon 6850 or 550 ti.
Haven't looked into PSUs too much but figured a cheap 500w would probably suffice! Cases are a bit of an afterthought as well but something cheap would be cool!
SLI or Crossfire: Maybe (In future)
Monitor Resolution: Will be quite high as I plan on running it through my 50' tv
Additional Comments: I'm quite set on the motherboard choice as it opens up the possibility of possible sli/crossfire in the future as well as overclocking! (though not on the i3). The main decision comes between processors, ideally I'm aiming for something that will come under budget-range but still at least last for a fair while and provide a good base for future upgrades. I'm just wondering if the i3 will allow the budget to stay low while providing some longevity, whilst the new ivy-i5s look pretty sick with the overclocking ability but come at an extra £80 approx.
The 2500K is only 156.84 pounds, and is faster than the i3, and very slightly slower than the 3570K, but also cheaper, The difference at most will be 10 FPS, if you cmpare to the i3. If you can wait, IB i3s will come out, and sincethe i3 is unoverclockable, you should wait. I think they come out in the summer, but I'm not sure. http://www.amazon.co.uk/Intel-Sandybridge-i5-2500K-Quad...