i5s are nice processors, I was tempted by the 3570K with this build, but the
Add to basket item next to the i7 was just too tempting
The 3470 is a nice processor and will cope with most of what you throw at it, the only drawback is that you can't overclock it - but I don't know whether you planned on doing that anyway? If you wanted to get into overclocking, you'd have to go for a 3570K (the K denotes an unlocked multiplier - one of the requirements for OCing)
Intel Core i5 3570K 3.4GHz Socket 1155 6MB Cache.. | Ebuyer.com
When looking to buy your components, I would highly recommend eBuyer:
Cheap Laptops, Computers and Cheap LCD TVs | Ebuyer.com
After looking everywhere (OCUK, Scan, Amazon, eBay, eBuyer), I found that eBuyer was cheaper on all of my parts - I had to get one through Amazon though, as eBuyer doesn't sell it. So shop around, and you might save yourself a few quid

But watch it on eBay, things that seem too good to be true usually are - like that 3770K bundle for £20 (the CPU alone cost me £256...).
Tom
Tom