The GTX 970 will do what you want at 2k. The 980 and 980ti are more so 4K. I wouldn't reccomend buying a 980ti unless you are going 4K.

EDIT: Its just kind of a waste of money seeing as you will probably do 60hz which maxes out FPS at 60fps. The 970 should give you 70+, the 980 is going to do 100+ and the 980ti is better of course. To me it just seems like a waste of money seeing as the monitor is going to bottleneck it anyways. Even if you have a 120hz, I feel the 980 would handle that.

But maybe money isn't an issue at which point you can just buy the 980ti. Maybe you will go 4K too.

Thanks for the responses.  Always liked these forums for a reason.  
 
That is certainly quite an upgrade!  I did get the ACX bugger with a backplate.  Kinda excited for my early Christmas gift to myself....
 
I do have SSD's installed.  Good on that front. Power should be okay according to the link provided.  
 
I did opt for the 980ti as I *might* do the 4K thing as price drops happen.  The last round of upgrades was in 2012.  The 670 definitely met my needs...but it's time. ;>)  Fallout 4 is coming :P
 
edit: got this bugger.  Missed out on a rebate because I waited until today to hit the 'purchase' button.  edit: oops. :P
 
http://www.newegg.com/Pro...x?Item=N82E16814487142

Cool GTX
980Ti is about 8X as powerful your current 670; and is a inexpensive Titan X substitute with most of the same power.
 
ACX coolers require GREAT case air flow as the GPU heat stays in the case otherwise.
 
Reference - standard cooler does blow GPU heat out of the case - but tend to get noise at high fan speeds.
 
Hybrid Cooler is nice if you have room in your case and budget.
 
IMO, 4K without SLI is a waist of time. I have run 4K with the following EVGA GTX cards in 2Way SLI:
 
780 Ti Kingpins - (3 Gig Ram is a bit of a limit), 980 SC, and now Titan X SC
 
 
Check your power needs with:  http://www.evga.com/power-meter/
 
As long as your +12V rail can put out enough power and has enough connectors for the GPU you decide on - have fun and enjoy.
 
By the way ("It's been a long time since I have tinkered with my rig.") if you are not using a SSD for your primary drive - you will be very impressed by that change - make your PC come alive in speed - big difference in daily use - you will see the difference and not just measure it with a benchmark.  256 SSD are reasonable, I prefer the Samsung 850 Pro versions.
 
Good luck with your build.

Nicely done! I do not pretend to your level of knowledge on this, but I fully agree that the 980ti-I just installed a 980ti SC+, because the 780 wasn't enough to push Wild Hunt's pixels @ 1440p. The 6gbs vram means my Skyrim mods all worked together flawlessly for the first time, and Wild Hunt is darned near photorealistic. 
 
I also have a Samsung 830 256gb SSD, and you are certainly right. Everything comes to life. for games, it is mostly the entering/exiting areas that is most affected, but all gameplay is smoother with the SSD. I leave most Steam games on Steam, so a 1tb HDD has proven more than sufficient. 
 
For the OP, I have a 2600k i7 @ 4.2ghz with a AIO water push/pull setup, and my frame rates are more than adequate. Most reviewers say that even my long in the tooth CPU is not a bottleneck, and no recent chip is so overwhelming that an upgrade is necessary. 

fredbsd
Card is a beast.  Holy smokes.
 
Not that I expected anything different, however, it is always nice to have expectations exceeded.  EVGA has never once let me down (granted I am by no means an 'enthusiast'...just a hacker).
 

Congrats on your purchase! I love my 980 Ti. If you really want to have some fun you should try running a custom bios to realize the true power of the card and take advantage of your ACX cooling.