The SC is a factory over clocked reference model card. Nothing special on the PCB.

Ftw is a custom pcb, so it is supposed to better at overclocking, but it has less options for aftermarket cooling and watercooling, which it doesn't sound like you will be doing anyway.

Classified is meant and built for extreme cooling. Don't let the big numbers fool you, it isn't special without the proper cooling. It is just a bigger, beefier card built specifically to be used with liquid nitrogen and dry ice mixtures.

Your best bet would be the ftw for the slightly lower price, or the sc for the most options in the future.

Before doing so look at your supporting components and see if those components are going to help give you what you need to push any card to its maximum potential.

Fettle
There is SSC too. :p

With the given options we are to assume he looking at gtx 980s which there is no ssc.

If you just want to play games and and don't plan to overclock at all I'd go with the SC version.
For overclocking I'd not take the SC version because you have no Dual BIOS and OC with any Windows software is bugged with newer cards (OC with Afterburner leads to CLK/voltage shifting and can cause weird problems in idle later on for example)
 
If you wanna OC for gaming I'd definitely go with the FTW models since you have Dual BIOS, so you can modify the BIOS without much risks. (You can still fry the card when you set crazy voltages for example!)
 
I'd only buy the classified if you plan on overclocking for benchmarks with extreme cooling methods (like LN2)

All right, thanks for the feedback. I'm a bit more informed now. But perhaps I should specify my situation.
 
Currently, I have an EVGA GTX 760 SC of some description. I can't tell if it's ACX 2.0 or not, nor if it's either 4GB or 2GB (I believe the latter). This CyberPowerPC computer I received as a gift, and couldn't quite find the exact specifications for it, and everything on my computer just says "GeForce GTX 760." The transparent side of the case allows me to see it a little bit, and I was able to figure out that it's EVGA brand and an SC variant. It serves me very well, and I have no major impulse to upgrade it right now, as most games run on Ultra smoothly.
 
Still, I'm just looking to get the best possible experience, and plan on getting a 980 sometime soon (was gonna get a 970, but I'm not to sure about the 3.5 GB situation; what's the major difference between the 980 and 970?). I was just never able to really discern what was best between SC, SSC, and FTW. And then this Classified thing shows up and I'm pretty lost.
 
With regards to overclocking, I have no idea how to do it, or how much of a benefit it would be. I just play my games normally most of the time and never have to do anything special, as my computer is very strong. The other specs are as follows:
 
16 GB RAM
Intel Core i7-4820K CPU @ 3.70 GHz
64-bit Windows 8.1
 
So I'm not really lacking there, but I'm hoping to at least be able to play Skyrim on Ultra with a nice ENB at a stable 60 FPS. Right now my Skyrim looks fine with everything else I did, and I do enjoy the way the "vanilla" version looks, but I just want to try new things. Battlefield 4 also runs at a stable 60 FPS on High, with a few select settings maxed out beyond that. Crysis 2 is similar. Everything else I own runs flawlessly (except for Arma, I can't please that game).
 
I'm just trying to make an informed decision on which card to upgrade to. I'm not an overly technical person, I just want Ultra 60 FPS at 1080p, which I get most of the time. I'm not concerned about cooling, as most of the volume of my PC case is just air, and the fans and the vents always work fine. The air from the fans only feels a little warm when I play the heavy stuff like Crysis 2 or long sessions of Battlefield 4, I think.
 
There's everything that'd probably need to be said. Again, thanks for the help!

255killer

Fettle
There is SSC too. :p

With the given options we are to assume he looking at gtx 980s which there is no ssc.

Who is we?. YOU are free to assume anything you want.
 

Luminoth Prime
All right, thanks for the feedback. I'm a bit more informed now. But perhaps I should specify my situation.
 
Currently, I have an EVGA GTX 760 SC of some description. I can't tell if it's ACX 2.0 or not, nor if it's either 4GB or 2GB (I believe the latter). This CyberPowerPC computer I received as a gift, and couldn't quite find the exact specifications for it, and everything on my computer just says "GeForce GTX 760." The transparent side of the case allows me to see it a little bit, and I was able to figure out that it's EVGA brand and an SC variant. It serves me very well, and I have no major impulse to upgrade it right now, as most games run on Ultra smoothly.
 
Still, I'm just looking to get the best possible experience, and plan on getting a 980 sometime soon (was gonna get a 970, but I'm not to sure about the 3.5 GB situation; what's the major difference between the 980 and 970?). I was just never able to really discern what was best between SC, SSC, and FTW. And then this Classified thing shows up and I'm pretty lost.
 
With regards to overclocking, I have no idea how to do it, or how much of a benefit it would be. I just play my games normally most of the time and never have to do anything special, as my computer is very strong. The other specs are as follows:
 
16 GB RAM
Intel Core i7-4820K CPU @ 3.70 GHz
64-bit Windows 8.1
 
So I'm not really lacking there, but I'm hoping to at least be able to play Skyrim on Ultra with a nice ENB at a stable 60 FPS. Right now my Skyrim looks fine with everything else I did, and I do enjoy the way the "vanilla" version looks, but I just want to try new things. Battlefield 4 also runs at a stable 60 FPS on High, with a few select settings maxed out beyond that. Crysis 2 is similar. Everything else I own runs flawlessly (except for Arma, I can't please that game).
 
I'm just trying to make an informed decision on which card to upgrade to. I'm not an overly technical person, I just want Ultra 60 FPS at 1080p, which I get most of the time. I'm not concerned about cooling, as most of the volume of my PC case is just air, and the fans and the vents always work fine. The air from the fans only feels a little warm when I play the heavy stuff like Crysis 2 or long sessions of Battlefield 4, I think.
 
There's everything that'd probably need to be said. Again, thanks for the help!

There are some games that if you max out, even at 1080p, they wont give 60FPS. :D
 
970 if you dont care about it's reputation is a good bet otherwise shell out more money (and then some more for SC, SSC or FTW flavor) and get the 980.

Personal opinion... If you don't intend to OC then I don't think you need to be overly worried with the VRM's,  the cooling, etc.  All EVGA cards come with great cooling / more than ample for their rated clock speeds.  I'd go with the best bang for your buck.
 
... However, I'd put an amendment on this in terms of future proofing down the road.
 
 
There's only so much that you can OC a card, and there's always a tradeoff.  [simply put, stability is under appreciated]  If you later on decide that you want to game at 4K, or if you want 144hz 1440p, etc, the only good way to get up to high framerates with such a setup is with multiple cards.
 
(of course this depends on the genre of games that you're in to, but I'm assuming FPS's)
 
 
When you SLI, it's a bit counter intuitive on the OCing and cooling until you think about it a bit.  There's limits to how much you can safely draw current-wise from the PCI-E bus (not the 6/8 pin connectors).  The performance gains also tend to be smaller as removing heat, especially with non ducted cooler (non reference design) work worse than reference coolers [alot of the time] in a confined space.  It gets alot rougher to remove heat from the chassis whenever you have multiple cards exhausting heat "in to" the case.
 
You might decide later on that you want to go the liquid cooling or AIO route to keep the machine cooler with 2+ cards.  It's alot tougher with non reference designs (to find suitable cooling solutions and mount them).
 
 
 
EDIT:
 
On the differences of the cards, the "big" difference is as people laid out in prior replies that there's factory OC'd "reference" boards and non-reference boards.  If a card is a reference design, that's more or less saying it's the unmodified design as provided to manufacturers by NVidia.
 
-Manufacturers of course improve on these designs.  They expand the board, they add more voltage regulator phases, or otherwise beef up the card to permit it to safely take more current, such as adding two "8-pin" power connectors instead of a 6pin and 8pin, or dual 6pin.  This is the key difference.
 
The clock speeds may be similar, yet you're comparing EVGA's board design vs NVidia's stock board design.  In theory the non-reference boards can be pushed harder or to higher voltage limits.  HOWEVER, this does not guarantee that a non-reference board will get higher clocks, as all GPU's do have effective ceilings that they just won't push beyond no matter how much voltage you give them.
 
 
Put another way, it's the fabled Silicon Lottery.  Your card is rated to run at the speeds that EVGA sells it to you, clocked at, out of the box, and no matter the card you buy, it will run stable at that speed (or EVGA will fix-it / replace it).
 
---Beyond that speed you're on your own.
 
Or rather, you could buy a Classified that cannot push past the stock-speeds, or only goes +20mhz.  It's rare to find a Maxwell that doesn't overclock well, 'but' no matter the card you buy there's always the potential of getting a dud-chip.  This should always be considered, because at the end of the day there's a more important metric than performance. 
 
(Guaranteed performance per $$ in your purchase, which can also be called guaranteed 'stable' performance per $$)
Just-playing-games w/o problems is also often overlooked.