By 'lasting 3 years', I didn't mean 'play all games released within the next 3 years at full settings', just 'still usable and quite decent'. I probably shouldn't have said thatGvaz said:For emulating those things get a i5-2500k and any old graphics card. I'm afraid you wont find anything that will last you for three years unless you buy the most bleeding edge parts, especially with new hardware close on the horizon.
get 4gb or 8gb of ddr3 ram around 1333, get either a gtx560ti or a gtx570 at most. (these can more than handle the games you listed and others)
I don't know the prices for things in pounds though so that should be a good starting point.

Anyway, I've drawn up a list of some of the components from Novatech's site:
Processors:
2nd Generation Intel® Core i5 2500K 3.30GHz Socket LGA1155 (£167.99) - I'm fairly sure I'll be going with an i5 and overclocking it. Alternatively, the i7 is about £70 more (£239.99); I'm still deciding whether or not it would be worth it for me.
Gainward GeForce GTX 460 "Golden Sample" 1024MB GDDR5 (£119.99) - is it worth splashing out an extra £57 for a GTX 560 Ti (£176.99)? I don't think I'll spend nearly £300 on a GTX 570 (or for that matter, more on higher).
Various types of memory:
Corsair Vengeance LP 8GB (2x4GB) DDR3 PC3-12800 C9 1600MHz Dual Channel Kit (£46.98)
Samsung Spin Point F3 SATAII 1TB 32MB Cache Hard Drive <8.9ms 7200rpm (£46.98) - I really don't think I'll need anything bigger, seeing as the 250GB disk in my MacBook is still only half full after 2 years of use.
Crucial RealSSD M4 64GB 2.5" SATA 6Gb/s Solid State Hard Drive (£83.99) - A bit of a pricy add-on, but apparently it makes quite a difference. 64GB should be enough if I'm going to use it for the OS and programming IDEs, right?
Miscellaneous:
Novatech Corona Micro ATX Tower Case With a 450w PSU - Black (£25.98) - I don't want a huge and flashy case. Only thing is that it might be too small - would I be right in thinking that smaller cases are more prone to overheating?
Coolermaster Hyper 212 Plus CPU Cooler (£22.00) - Since I'll be overclocking, I figure I'll probably need some kind of cooling.
I have no idea about what kind of motherboard I'd need. Considering I want to overclock the i5, does anyone have any suggestions?
Input/output:
Not sure at the moment... Probably going to buy a cheap keyboard/mouse such as this Logitech one (£11.99)
Monitor-wise, I'm looking at 1080p ones right now. Novatech's own-brand monitors (£79.98) are far cheaper than the competition. How big is the difference between a 10000:1 contrast ratio and this one with a 1000000:1 contrast ratio (£114.98)?
So far, using the lower-end options above, it comes to £605.88; a GTX 560, better monitor, and i7 bring it up to £769.88. The motherboard will add a chunk to it, but I still have money to spare.
So, can anyone help me with the rest? Choosing a motherboard, maybe a different case/power supply, advantages of a GTX 560/SSD/1000000:1 contrast ratio screen?