So, is the 7770 crossfire option out the window? I'm not being partial, but are the downsides of crossfire really so bad that getting 7950 like performance at a lower cost an invalid option?
look for the games you listed:
Gaming- bf3, ac3, borderlands 2, deus ex, diablo 3, skyrim
you want nvidia, take a look at those benches
in the link prototype posted. though BL2 isn't listed, you want a card that can handle physX for the game or it looks like crap with the difference.
keep the 660.