Far Cry 3 has beautiful enivronments XD I played the Crysis 3 demo but of course that is multiplayer and i know the Singleplayer will look different. I dont think ill be able to max it out honestly though.
A 680 should do the job for Crysis 3 (unless, of course, you have cash to burn and can plop down for a 690/Titan). Also to note - Crysis 3 takes advantage of multi-core CPUs, so you'll be OK on that front (clock speed?). And 16GB of RAM is plenty for any PC game, as you know.