I'm looking into upgrading my current PC and i was thinking dual GTX 780 cards running in 2-way SLI, should i do this, or just go single and upgrade later?
I can't see a situation where spending $1300 on GPU's would be necessary.
BENCHMAAAARKSSSS!!!!
Seriously though, hardly anything needs that much power right now. I mean, sure if you have the money to blow and don't want to upgrade again for 5 years then go right ahead.
If you want to be sensible and get a good card for gaming that will treat you nice and age well, either get a single GTX 770/680 or get a Radeon HD 7970 Ghz. No point in spending the extra moolah on a mere 10% performance leap. (According to most benchmarks.)
Edit: It's not even a leap, more like a slight suggestive shuffle.
What res are you running at? If its 1080p don't even bother. But if you're multi monitor gaming go for it, if you have the money to burn.