Just thought I would post to correct some of the information on here, firstly games consoles are manufactured and distributed at a loss or at best at cost, the reason being the manufacturers need to ship alot of units to encourage publishers to the platform. Games consoles are manufactured using the latest technology, so when they first come out they ARE FAR MORE POWERFUL than any gaming PC you could build for the same cost. <-- Just correcting what someone said earlier, obviously if you compare a £2000.00 gaming rig to an Xbox 360 thats different.
Going back to the OP, I would go for an 1155 Ivy Bridge setup, in terms of performance to cost ratio I think that is the best way to go, it would cost considerably more for a 2011 chipset setup:
Motherboards -
http://www.scan.co.uk/shop/computer-har ... -intel-z77
Processor -
http://www.scan.co.uk/shop/computer-har ... -bridge%29
If you take a look here:
http://www.cpubenchmark.net/high_end_cpus.html
You will see that this processor is right at the top of the list, my processor and motherboard which were considerably more expensive are much farther down. If the PC is a pure gaming rig, you could go for an i5 as the graphics card is more important, graphics cards are optimised for performing complex calculations relevant to 3D, so that work is not done on the CPU.
In terms of RAM someone here said you need loads, you DON'T, huge amounts of RAM are for high end 3D rendering and other long intensive tasks. (When I say 3D rendering I mean making feature length animations like Pixar films etc), 6-8G should be more than enough, I have 6G I think in mine and even when I run a really intensive 3D game I dont use nearly all of it. If it comes down to an option between 6G of really fast RAM and 8G of slower RAM go for speed. You wouldn't use 12G running Crysis or BF3 or whatever. Try to go with someone like corsair they have a really good reputation when it comes to RAM. My 6G at the time was the fastest ram you could buy.
http://www.scan.co.uk/shop/computer-har ... hz-plus%29
Graphics are a grey area you have the Nvidia camp and you have the AMD camp, Nvidia camp will say the cards are more expensive but better quality and have better support, AMD camp will say you get more for your money... Its upto you on this, I went for Nvidia because it had better options for 3D etc in the future and I read that CUDA cores kick ass compared to AMD's (you'll notice that AMD cards have like 1000+ cores, whereas an equivalent Nvidia has 320+). My decision turned out to be wise, a friend of mine that built a rig at the same time (a considerably cheaper one) had to buy a new Nvidia card because he was having problems with a particular game and his AMD card. Anyway graphics you will have to make your own mind up... Just get the best you can afford...
Power, theres 2 options really, modular or not... Modular is where you plug in what you need so you dont have loads of wires everywhere, non modular is the opposite you have a harness of wires whether you use them all or not. I would go for 700W or something like that, try to stick with a decent brand so it is less likely to develop faults.
Erm HDD's and SSD's, well SSD's are ALOT better reduced loading times better performace yes, but they are expensive, I got a 60G one when they first came out and it lasted a year before it just died, it came with a 3 yr warranty so I got it replaced but I had lost quite a few of my files, if you can afford a SSD then get one but dont take it out of your budget for the other stuff. You will probably still need a traditional HDD for raw storage aswell anyway.
And I think thats about it, the other elements I dont consider to be part of a gaming rig, Monitors, Mouse, Keyboard etc they are nothing to do with raw processing power and should not be included in your £600 budget otherwise you wont get even a half decent rig.
As for Ebay etc, unless its 2nd hand you will probably find that most of the rigs around your budget are based on the 1155 chipset, obviously the seller will have a mark up for building it, so you would probably save some money assembling it yourself.
Not to sound rude but £600 for a gaming rig is a fairly low budget, the above is about the best you will get for your money. You would have to increase your budget considerably to get a really high end gaming rig.
