If it's hard to justify the £300 price for a stock version of the card, though, is the 50MHz overclock Zotac has given its AMP! Edition worth an extra £70?
Certainly it looks like good value for money. The AMP! Edition's giant copper cooler used on both this and Zotac's GTX 480 AMP! is possibly the biggest we've ever seen on a graphics card, and also makes it a triple-socket sized card too.
It's not hugely heavy, but if you're planning to build an SLI rig, this is not the card you're looking for.
Internally, a 100MHz increase on the standard speed of a GTX 470s shader cores and another 54MHz on the memory should give it a lift over a stock card, but by how much?