GPU Upgrade

I'm looking at upgrading my GPU. I currently have an i5 3570k @ 4.4 Ghz, 8GB of RAM, and HD 7950, and a Corsair TX650 650w PSU. I currently have a 1080p 60hz monitor, but I'm considering a multitude of upgrades from it in the future, such as 1440p 60hz or 144hz, 1080p 144hz, or even 4k. 

I don't exactly have a set budget, but the cards I'm currently looking at are the R9 290, R9 290x, GTX 970, and GTX 980. I don't really have any preference one way or the other. One of the things I like about the 970 is that I should be able to run two of them on my current power supply, which would be a nice upgrade in the future. Of course, based off of Logan's review as well as what many people say on this forum, the GTX 970 is not trading blows with the R9 290x and is in fact slower than the 780, contrary to what other reviews say.

What do you guys think would be the best card to get, especially in terms of price/performance? (I live in the US)

Are you in a mad rush to upgrade?  If not I would wait a bit - the r9 3XX cards should be out soon(ish) and even if they are out of your budget - they will drop the price of the 290 and 290x.

If you have to upgrade NOW I would probably grab the GTX980 - lower tdp means less heat and noise, and also you may (and i say that hesitantly) be able to SLI later with your PSU.  It also has native DX12 support which the 290X does not have IIRC

i would say 980, I currently use a liquid cooled R9-290x and for what i paid for my card is what the 980 is going for now, about $530. It will be a good investment and you will be happy.

I'm sort of thinking I'll wait until black friday/cyber monday and then try and pick up a couple 970s or possibly 290s/290x's, depending on price.