GTX 680 Lightning Edition 2GB is $630
the normal edition 2GB is $477
Classified 4GB Edition is $590
and Classified Edition doesn't even look that good.
..
2x4GB SLI is overkill. and i dont think i'll need to over clock anytime soon.
..
so, i am thinking 2x http://www.amazon.com/EVGA-GeForce-DisplayPort-Graphics-02G-P4-2680-KR/d...

TITAN is way over priced and will be outdated in 1 or 2 years. and then to SLI that with another $1000 TITAN is expensive and stupid..