Off-Topic Discussions

This isn't new but it might be of some help to you.

www.hardocp.com/article/2012/07/18/pci_express_20_vs_30_gpu_gaming_performance_review/14

THIS is the 780Ti you will want to get. It's 40 bucks more than the Stock card, but it's overclocked, has better cooling on it, and is sold by EVGA. The #1 NVidia partner in the US. Hands down best tech support in the industry, they ALWAYS answer and are ALWAYS helpful.

www.evga.com/Products/Product.aspx?pn=03G-P4-2884-KR

Your board can probably upgrade to the newest AMD Black chip. What was your Socket number again? There's several 8 core Black solutions out there, around 4Ghz. This would tide you over for more than 2 extra years!
Also, i agree that the 780Ti is a MUCH better idea than a whole new build. Good choice on card, Titan is overkill and a WASTE. In fact 780 TI actually outperforms the titan in some cases. Remember that the Titan is basically just an NVidia Quaddro card sold to the general public. Same as Xeon CPU's perform worse in gaming environments than standard Intel CPU's, the Titan performs worse under some situations than GTX 780Ti does; even though the chip is the same on both cards. Also, Titan has a LOT more memory on it, which helps in games like GTA 4/5, while the 780Ti has less ram on it, it's optimized for gaming. Tradeoffs are only based on your needs. Titan is a bit overpriced for a single GPU as well.
Also, SLI not necessary. there's NO game out there this second that would not run at 60FPS with a 780TI. Remember that by the time a card comes out, it takes about 1 year for a game to utilize the potential of that card. Add another year for games to surpass that GPU, and that gives you 2 years GUARANTEED between necessary upgrades. Just remember that GT and GTX are very different when it comes to GPU's. a GT 755 vs a GTX 760 are SIGNIFICANTLY different beasts. One has almost double the performance of the other. GT is much slower than GTX.

Hope this helps