Ok, I'm not sure the OP has the info he needs.
Cliffs :
670 stock and 680 stock are 5-15% apart, and they are both available in multiple memory configurations. They are very very close.
670 'vanilla' comes on a weaker PCB with less effective cooling and power delivery.
680 'vanilla' is a bit beefier, with improvements in both of those.
670FTW and other specialist 670s come with higher clocks and usually the 680PCB along with improved coolers at least as good as stock 680, sometimes better.
680OC/etc editions are even better still, but not hugely so.
670FTW is basically identical to stock 680 performance in multiple reviews. Which is why I bought one (and I love it).
1G i7 + OC will NOT cause you to lose out on any performance in current games. Newer is nice and all, but don't worry over that.
The only real question for you is 2G model or 4G model. For 1080p (or the 1920x1200 I use), 2G is enough. For 1440P and higher (or for heavy texture mods like for Skyrim), you want the 4G version, trust me.