PC build advice - GTX 970 SLI vs GTX 980 for the long run?

[Weelob]

Hey guys,

I recently purchased the retina iMac saying I probably didn't need to game that heavy games and the M295X in the iMac should be fine for the games I do play today. However I have then thought that spending ~£2360 on a machine where I personally see a short lifespan in, is kind of a waste of money even though the machine is super nice and fits my needs today.

What I need is something I will be still happy to own in a year or two, therefore I have chosen to cancel the iMac purchase and build my own PC instead.

Budget wise it doesn't matter if it's SLI 970 or stand alone 980. I'm personally leaning towords buying one 980 now and a new 980 when / if it's needed for SLI config.

This is the setup I'm thinking about buying at the moment:
Intel Core i7-4790K
MSI Z97 GAMING 5
HyperX Fury DDR3 1600MHz 16GB Black 2x8GB
MSI GeForce GTX 980 "Twin Frozr V"
Samsung 840 250GB
WD Red 3TB
Corsair RM750
Corsair Carbide Air 540

Any suggestions on better parts and such would be much appreciated.