E3, what card did it use?

To be honest it's impossible to know.
There isn't such a thing as generations within PC gaming (not unless you talk about graphics card generations and there are about 20 of those).
Also, you can't accurately compare against the console generations because there are too many variables e.g. whats the primary development platform, what are the confirmed specs of the next gen consoles, are the guys coding it lazy and retarded meaning the PC version needs a super computer to run it (here's looking at GTA4 when it was first ported!).

I really wouldn't worry about it until those games are closer to being released.

For the time being just be happy that you can play the games that are out now, cause trust me, you'll go insane if you keep trying to guess these kinds of things.

The first guy that reply is definitely right +1,

for an example like cpu, i7 920 is release in 2008 and still compatible this year and still going strong a for a year or more,

But it dif for a gpu, the 680 almost completely destroy 580, but then i cant make sure that the 780 probably out next year to destroy it predecessor 680, but u can always lower the setting on future game, which is kinda.. Not satisfying

That the advantage of overcloking, it make ur cpu compatible with upcoming gpu,

After looking at benchmark, most gpu not fully capable of gaming at 2560p ultra res,(like mtro and bf3) with over 120fps if i was right
Also benchmark at 3d gaming, sli microshuttering

It will be crazy to predict the future unless u working at nvidia,amd company or AAA+ games
and buying the latest gpu every year,

I think the best think you can do is wait for the next series after the gtx 7xx the gtx 8xx
Also i have no confirm information that the gpu will be name that way.  

At least u can wait for 2-3 for the next gpu upgrade,

Didn't E3 use a dual sli 580 configuration?

its very unlikley that a gtx 680 will be irrelivant when the new gen consoles arrive as they wont have anywhere near the power of that card. they are gonna be the roughly the same powere as a 6770 or gtx 550ti if the rumours are correct.
personally i wouldnt worry about the next gen consoles as they will barley register with pc gamers unless they cost $1000 and are way above what is currently being toted about as there specs.
i have a 5870 and its now approaching 3 years old (next month for mine) and is now considered mid range. your gtx 680 will probably last just as long as mine if not a little longer.
im only now considering selling it as the gtx 770 will be here soon (jan/feb if i remember rite) and it may be as much as late 2013 early 2014 b4 dx12 appears. yes its coming...
but dont worry most games still dont fully support dx11 2 and a halfish years after launch. so your card has at least 3 good years in it regardless of what happens with consoles...
personally i think this next gen of consoles may well be the last as tablets take off in a big way of there next 5 years i can see consoles being totally irrelevant to the casual gamer as the pads will have more power, better gfx and portability...
pc desktops on the other hand will just keep growing in power so will always be relivant unless they suddenly switch to that onlive format of gaming which to me still seems like a novelty. and a bad 1 at that.

a thread that i read is that the gtx 7 series will be out atleast feb-april next year,
and that time u can see skyrocket price, and august u can only expect it in most shop shelves, when u think about buying it, the next gen Gpu will come out,, there go the cycle...