MONITOR: Benq G2222HDL LCD LED 21.5" DVI-D Monitor - £108.76 / I dont know to much about monitor's so am open for suggestion. I would like to be able to use my PS3 through it. http://www.ebuyer.com/product/177132
for gaming and surfing the net, you could easily save money and get a cheaper motherboard, and by opting for the i5 2500k you loose very little gaming performance. By a cheaper motherboard i mean something like the p8p67-pro from asus or any from this review by toms:
Also I would recommend the ati 6950 over the 560ti, plus if you buy the 2gb version it can be flashed (not guaranteed but good chance) to a 6970.
The 6950 in crossfire has better performance than the 560 ti
from toms: "AMD dropped half of the Radeon HD 6950's onboard memory to give us this 1 GB model, and the price dropped accordingly. At $250, the existence of this card makes us question why anyone would save a mere $20 to purchase an inferior Radeon HD 6870 or GeForce GTX 560 Ti."
amirp is right about the CPU, you gain virtually nothing from hyperthreading in games, you would need to be doing other things more processor intensive to justify the extra cost.
I also wouldn't spend £300 on a motherboard, but it seems like you are still under budget, so you could resort to considering cutting back there if you find that you are over budget or want to cut costs a bit.
I wouldn't choose the HAF X for a quiet build, but that's personal choice.
The power supply really is crap tho.
Here are some options:
XFX Pro 750W Core Edition 80Plus Bronze £70 http://www.ebuyer.com/product/241552
This build down below contains dual factory over clocked gtx 560's in SLI. These cards have beaten that MSI 560 in every benchmark posted so far. They are clocked higher, with room to spare. I didn't add the keyboard, mouse, etc.. seeing how those are personal items.