Need help choosing parts

[Nipplenator]

So I am finally upgrading, I already have some parts on the way, namely an i7 6700k, Asus z170 Deluxe and 32gb Kindston Predator ddr4.

BUT!

I will be using a BenQ XR3501 - res: 2560x1080, 144Hz and I cannot decide on a graphics card...
I was thinking about buying two 980tis since they dropped in price.. two 1070s are slightly cheaper, less cuda cores, but i will be only gaming, But im not sure how futureproof are these solutions
So the 3rd option is to buy one 1080... Question is: Will it last for atleast 3 years? I do not plan to upgrade in the next 3 years. But games are more and more demanding each year

What do you think is the better option?

 

[Zeinone]

Honestly, the 1080 is a more future proof card, but since your monitor is a 21:9 1080p monitor, even something lower than a 1070 would push it to the max at max 1080p settings. If you plan on upgrading your monitor to a 4k then a 1080 would be perfect, 2k - 1070, 1080p - the upcoming rx480 will probably smash 1080p

[Matias_Chambers]

I think you should go with the 1080 because some games don't work well with SLI and the 1080 is more than enough for 1440p.