if you want cheap as possible, and use it for gaming, get an i5.
i7 quadcore, 4 cores are only used for video editing.
there arnt any games using the quad cores.
go for at least 6GB, later maybe add 2 if needed.
Better go for a more powerfull vid card than a core.
try to go for a 2gb vid card.
Also, DO NOT buy a pre-made computer, meaning a computer that has all the parts fitted. If you can buy all the parts seperatley and fit them together yourself you will save yourself £300-£400
The best current AMD CPU is 5% behind performance wise compared to the i5-3570k, Intel are far ahead performance wise. If he's going for i7, he clearly has money to put into it, which would be far better spent on an Intel CPU build.
If you can wait 6 days and the new 4th gen intel (haswell) then I suggest it for a desktop.
Intel i5-4670k & i7-4770k.
First of all please name your max price. So I can find the best parts for you at the max price.
If what your looking for is the fastest single thread operations with PCI Express 3.0 with slightly lower power consumption and don't mine the cost, then get Intel for its widely known superior core to core performance. Recommend if using NVIDIA SLI or CrossFire (2 GPUs or More)
Actually Craig, The AMD FX-8350 & 8320 is faster than the i5-3570k with the most recent games that support multi-core rendering like Crysis 3 and BF3. AMD is superior in multi-tasking, Photoshop/Sony Vegas Video Editing due to large L2,L3 cache and 8-cores
The AMD FX CPUs are slightly slower in single thread operation but what makes it up is the lower pricing to the Intel i5 3570k & Intel i7-3770k
One of reasons for the slower operation in the AMD Bulldozer/Vishera Architecture is due to the large L2 cache (2MB per core) compare to Intel's (256kb per core) with has high timings/latency causing a bottleneck for some single thread programs, different Floating Point Operations and silicon nanometer manufacturing process.
So in end: Intel: Fastest Performance at a High Cost AMD = Low Price and Great Performance
Lastly I recommend also trying out Windows 8 if you haven't try it yet. As performance is even better both Intel and AMD instead of Windows 7.
Note that if you have a copy of Windows 8, Microsoft announced that Windows Blue (8.1) is free for download.