Looking at the Vega64 reviews, the answer to the question of the OP seems to be that, given that the performance of both is roughly similar, go for the cheaper one.

So, if the 1080 is still the cheaper option, go for it.

Seriously....the 64 seems to be pretty much garbage. Way too power hungry. The 56 though seems to be a good alternative slotting in between 1080 and 1070 powerwise, but is also more power hungry than a 1080.

That said it seems the AMD cards will gain huge performance jumps on Vulcan and with more optimised games really using the higher bandwidth.

I'd still recommend the 1080. You can't go wrong with NVIDIA in my experience.

And yet all the benches aren't completely pin point accurate to one another either. They tell a similar story, but the story isn't 100% to the dot accurate, but I guess you'll let that pass but anything else from anyone that isn't a benchmark site is busted or "anecdotal".

I'm not even trying to change your mind when there isn't anything to change in the first place. I simply told you my side and you rolled with "your rig is busted, that's a fact, it cannot be denied" and then sided with benches and yet I've managed to run other games well enough, but that's then amounted to "anecdotal", which is a classy way of saying "unreliable and useless info, therefore you're wrong". 

Yes, you apply it to everything, which is why you hardly think you're wrong most of the time. I'm watching you duke it out with someone else on this very thread and you're cock sure that you're right all the way.  You claim you'll admit to being wrong, yet I've hardly seen you do this in all my years of being on here, so is that to say that you have never ever been wrong on here at all?.

Well, if you max out the GTA V settings, it can be taxing in 1440p in some areas of the game, even with a 1080 Ti: http://www.pcgameshardware.de/Radeon-RX-Vega-64-Grafikkarte-266623/Tests/Benchmark-Vergleich-vs-Nvidia-1235712/

AMD is much cheaper if you consider the price of the monitor. If you're so serious about gaming that you invest is such an expensive card, you can't justify not buying a FreeSync/G-Sync monitor with a high refresh rate. FreeSync monitors are MUCH cheaper, especially if someone is interested in the extra value packs AMD offers, which includes $200 off of a sweet 34" 1440p Ultrawide Samsung FreeSync monitor (100 Hz I believe). nVidia can't come close to that offer.

Also, Ultrawide Masterrace!

Still, I'm keeping my hopes up for non-reference Vega 56 shipping with unlocked BIOS, or people creating a solution for this 56 can be a legendary card.

Too much power draw, seems as if AMD will never match the efficiency roadmap Nvidia is on.

Unless on a Freesync monitor, i'd be going GTX1080 here.

You guys clearly missed out on being burned by Fermi

When it comes to the future, don't judge it solely on how Vega performs. Navi will be the first GPU designed from the grounds up by Raja Koduri and it is said to take advantage of Infinity Fabric, similar to Ryzen, so it can be worthwhile. The question is when it's going to come out...

The more I think about Vega, the more I see it as a good card, but way too late to the party. AMD managed to round out its offer with high end cards, Pascal + Vega is a very good and competitive response to Pascal. But Pascal is over a year old! Vega is way too late to the party I mean, Volta is already out! Not the gaming consumer cards, but the V100 is already out! And while Vega can trade blows with Pascal, I don't expect it to compete with Volta. Vega 56 is the only card that has the potential to sell bigger numbers, especially if they keep price low and unlock BIOS.

On the other hand, we can expect prices to get lower in the next 6 months (if mining craze passes obviously...). Pascal cards should drop in price both because of Vega 56 and upcoming Volta. Competition is always good for customers

The performance is slightly in favor of the 1080 but the power usage is LARGELY in favor of the 1080, that counts for $$$ difference if there is one, 1080 is the solid choice

He only asked for a GPU advise, so let's not move that discussion into other things like monitors because we don't know if he's also planning to get a new one or even if he cares about faster than 60Hz monitors or things like FreeSync/G-Sync. 

In Vulkan titles Vega 64 is much faster than a 1080, and in DX 12 they trade blows all the time, albeit for the fact that when the 1080 wins, it is by a small margin, and when the Vega 64 wins, it's usually with a bigger lead.

In DX 11 the 1080 is usually faster.

Power consumption is clearly better on Nvidia cards, but that will only matter based on how many hours a week Turkish play, because at idle, where most cards spend their time, the differences are minimal (and that also depends on the rest of the build).

I disagree, this is too important a factor to completely ignore it. Buying a GPU with a monitor in mind gives easily the best result and gamers should always keep it in mind.