You can see from the benchmarks the Zotac GTX 460 1GB edition is by far and away the fastest spin of this new card in any performance metric you care to throw at it.
EVGA's stock GTX 460 768MB though doesn't suffer too much by comparison, but for only a touted extra £20 for the larger memory pipes you'd be crazy not to save just that little bit longer for the better card.
DirectX 11 performance 2560x1600
DirectX 11 DiRT 2 2560x1600
DirectX 11 DiRT 2 1680x1050
DirectX 10 Just Cause 2 2560x1600
DirectX 10 Just Cause 2 1680x1050