Currently 2 gtx 780 but am waiting for new HBM2 graphic cards.
But in features and build quality which one is best. Price not an issue.
Most people as I have a good idea of what reviews are available online, but the poll shows people's experience and opinion. For future proofing the only thing is to choose greater than current capacity with an educated guess.Seasonic and the EVGA I'd recommend just from name brand, do a bit of your own research when buying things.
I'm starting to hate people just throwing a poll up these days, there is never a best for future proofing, especially when you have no idea what you are going to do in the future in reality.
JonnyGuru is always good, the look for sales on things from there.
Just don't buy a cheapo for starters.