GTX 780 or GTX 780TI?

The 780 Ti is a better card, but it's probably not worth the price premium you'll have to pay. Most games on the market right now will play superbly on both cards, with the 780 Ti giving you higher frame rates, which you may not notice (I probably wouldn't notice).

Short answer: it's probably not worth it unless you want the bragging rights of having the fastest consumer-based graphics card on the market today.

By the way, I run an FX-8350 right now and I love it, but if you want to maximize the performance of that video card, you need to go with an Intel Core i5 or i7. All the benchmarks I've seen show you get better performance with the better CPUs, and Intel rules the high-end CPU world right now. My rig is great (an FX-8350 on an Asus 990FX Gen 3 Rev 2.0), but the i5's match my performance in most benchmarks (and in some cases exceed it) and the i7's blow mine out of the water - with the exact same video card.

No it isn't worth the extra cash. $200 USD more last I checked.

I own a 780 GTX and the only game I can't max out with optimal performance is Crysis 3, but I don't care for that game. My native resolution is 1080p.

get 780ti its worth it i own one upgraded from 770