I'd imagine a gtx460 would push high/very high at 1680x1050 in crysis 2. Considering the much smaller maps and higher performance, it'll be perfectly fine.
Also, if someone else blindly recommends an expensive gtx5 series card without justification (i.e. the computer is going to be very high end) i'll beat them with a stick

Summary of recommendations based on price/performance segments:
gtx460 768MB is awesome for £100-125
hd6870 (or even better, a hd5870) is win for the £150-200 bracket
*****Now passing into less performance for your hard earned money****
hd6950 is awesome for the £200-250
gtx570 is the £250-300 card
and THEN:
2 x gtx460 1GB for £300-350
The gtx580 is NOT a recommended card at this time, too much money, not enough oomph. All the recommended cards win at their respective price points compared to competitors.