I just want to say I just bought a 4K monitor to go with my 980Ti. I thought it'd be a nice improvement, but nothing too spectacular, but holy shit it's amazing!
I ended up buying a 980Ti through EVGA in March (Step-Up, knowing the new cards would be out in May/June) to play Dark Souls 3. Already had a GTX 780, which was plenty powerful, but I can't stand playing games on PC below 60fps (with most, if not all eye candy maxed, if not set to "very high"). When I upgrade to 4k, it's going to be a TV. Currently still playing on a 1080p monitor and plasma TV. I don't have any faith in a 980 Ti being able to play at 4k with modern games at 60fps at all. Hell, the GTX 1080 will struggle staying at 50fps on most games and it's ~30% more powerful.
I do most of my gaming on my TV, and the games that require a mouse and keyboard seem to be few and far between now, especially in terms of their requirements (mostly just isometric RPGs anymore or something like Diablo 3, which I'll play on my older PC) and while I am very interested in 4k, it would actually make way more sense with a monitor than a TV, and I am holding off for a few reasons:
1. For 4k to be noticeable on a TV you need to either get a 65+++ inch screen, or sit two feet away from it.
2. Competing technologies are still maturing. OLED is the best of the best right now in terms of colors/black levels. It's even better than a Kuro plasma (best of the best plasma), but they aren't easy to mass produce yet, and the life expectancy is questionable right now as is input lag for gaming. Then there's the standard LCD, which still has shit black levels. To get comparable to a plasma, you have to buy an LCD that costs 3x - 4x as much to a cheap plasma. No thanks. There is also a new tech called quantum dots, which is just a new iteration on the LCD panels, but it does things much differently and the blacks don't suck at all.
3. If I wanted to get a 4k monitor for gaming, I would probably have to get a G-Sync monitor. While my card won't be able to push 60fps (min, no drops) reliably, it kind of doesn't matter with G-Sync. The frame rate will always be super smooth regardless. I don't really feel like paying $1500 for a monitor right now though.
There are however two extremely awesome reasons to upgrade to 4k, even if it ends up being a gimmick like 3D (for a TV and at a reasonable viewing distance); HDR and Wide Color Gamut. These two technologies are
huge for color fidelity and getting a realistic image. I am hoping that my 2009 TV lasts five more years. By then, there should be enough good TVs to choose from that have these two options that also have as good as plasma black levels, on top of not having tons of input lag for gaming. I am currently using a 42'', and it's served me extremely well. I'll probably upgrade to a 55'' though since that will most likely be the smallest of a premium TV.
BTW, I wasn't trying to rain on your parade. I am sure the picture quality difference is noticeable and amazing at the distances people tend to sit from a monitor. Not everyone cares about 60fps either and are perfectly happy with 30fps if it means they can play at higher resolutions. I've just become so spoiled by 60fps that it's hard for me to settle for anything less. Plus, as I said, I play most games anymore on my TV, and right now 4k would be a waste for me. I'm also banking on the 1080 Ti or the next more powerful card after it to be the cards that can handle 60fps at 4k without any noticeable drops. We're really close, but not there quite yet.
Side note: Does anyone here give a shit about the current consoles? I purchased pretty much every console up until the current generation. Bought a Wii U on launch day, and only ended up buying two games for it. Never bought an Xbone, and bought a PS4 for Bloodborne and exclusives (which looked way stronger than Microsoft's offerings), but I still never bought another game for the PS4 yet, and both Sony and Microsoft are about to officially announce their "new" consoles; and they aren't just like a slim version either. They have a lot of new hardware being added and they are both going to be releasing consoles now in the way that cell phone upgrades are handled. Apparently all games being developed from here on out are also supposed to be guaranteed to still work on the original PS4/Xbone, but with less bells and whistles. I would be jumping for joy if either of the current systems actually had libraries giving a shit about (if you don't also have a decent gaming PC), but they currently don't for me.
It doesn't help that this has been the generation of delays and remasters either. Most of the games that I really want to play are being released between this fall and next spring anyway, and not a few months after that the new systems will be released. WTF?