My daughters computer has 8800GT 512, plays games just fine. Of course it won't play BF4, but then again, neither do I. That said, its going to be hard to predict just what the future holds for games. With AMD powering PS4 and X-box one, it could be that next years games will follow that and be very AMD oriented, so the gtx 770 will suffer. Or maybe the games will be NVidia oriented, to draw the market away from the xbox/ps and the gtx 770 will shine.
its a 50/50 crap-shoot... either way, a GTX 770 is a damned good card specially for a single monitor, however, it will take a slight performance hit vrs the 4GB in a multi-monitor setup