I'm still rolling with my 780, no intention of upgrading this cycle... I run at 1920x1200, and it does fine for now. Mind you, I don't play competitive fps for anything... but for Neverwinter, World of Tanks, Marvel Online, and more, it does just fine. No speed issues at all.
ps: as for the 2Gb and 'more than 2GB' debate... I've been in favor of the 'more than 2GB' side of things for a while now. _most_ games don't need more than 2... but some do. And that number is not getting smaller.