If you want DX11, the why not?
Well it would be nice to have DX11 for BC2..However i went from DX10 to DX9 in BC2 and didnt see any diffrence in looks.
I would say if you plan on upgrading your complete system soon then dont upgrade the GPU now.
Also the 400 series are hot + eat the wattage up for the same (and in most cases) or with less FPS then its ATI counter part. Id wait for the 5850/5870 to fall in price and buy one of those vs 460. DX11 isn't that used yet and its not THAT great yet so its not worth the price.)
You mean the 8800GTS 512mb version? It had the G92 chip. I had that card!