would i realy need it on a 20inch at 1650x1050
some people say you don't really need it at 1680x1050
i wouldn't bother with a GTX at 1650x1050.
I agree with caithomas!if you want to play crysis then you need the best you can afford!
1680x1050 is a pretty high resolution so depending on which games you play (or want to play) you really do need as much pixel pushing power as you can afford! Crysis/High won't run 'smoothly for me using an 8800GT at that res, even with 0xAA

The GT is an awesome card but it can't blaze its way through everygame at such a high res. I'm not suggesting you rush and buy an 8800GTX but maybe just hang on a while and see what happens, new 8800GTS-512MB should be released next week. . .