Badimir Putin

I'm running a 6700K overclocked and two GTX 1080s in SLI overclocked on a Corsair RM850i. According to my in-line power meter, I never draw more than 500W from the wall. I'd say your 850W PSU will handle it splendidly.

I agree with this. I would be using my MX Master for gaming myself if it weren't for the lack of variable DPI and more thumb buttons (I prefer MMO mice with numpads for macros).

Dude, everyone has their preferences. Stop shoving yours down other people's throats.
 
If you demand 4K 60FPS, then don't even bother thinking about the current consoles.

I have an Asus PB287Q (4K 60Hz) hooked up to my PS4. Sure the framerate sucks, but I don't really care about that when it comes to a console, especially just playing a game like Crash, which I originally played on a 400x600 CRT TV and is essentially a platformer anyway. I do prefer gaming on my PC (obviously, if you looked at the specs), and I would MUCH prefer them to release a PC port for the games, but I'm not confident that Activision will do that in the future. I really just wanted the game as quickly as possible. Plus since then I've picked up a couple console-exclusives that I've enjoyed, like FFXV and Horizon Zero Dawn.
 
I don't regret my purchase, and I'll continue to enjoy it in the future.
 
EDIT: I'd also like to express my surprise at your response. You asked for people to recommend a path of action for you based on their knowledge or experience of it, then you berate them for making a suggestion?

I work as an Electrical and Control Systems Engineer for Pickering Associates, a full-path engineering/architecture/surveying firm.
 
Industrial plants contract us to do design engineering for any projects they currently have running. As one of the electrical engineers here, it's our job to design and draft the new electrical distribution (or make design changes to existing electrical distribution). As one of the control system engineers it's also my job to design and draft new plant-wide control systems (or make design changes to existing control systems).
 
Our clients also include commercial businesses that need electrical renovations or arc-flash analyses. We don't do anything residential.
 
It's a rewarding job. I work with a lot of awesome and incredibly intelligent people. I graduated from college with a BS in Electrical Engineering and a BS in Computer Engineering in May of 2016 and walked right on to my job here. I'm still learning, but it's turning out to be an awesome experience.

A small audio mixer would probably be your best bet. You can usually get 5-channel mixers for $30-$40 USD. This will allow you to put each device (computer, console 1, console 2, etc.) on each channel, and individually control their audio level as it mixes them all into a single stereo mix for your headphones. Most small mixers like that also have a USB connection that increases functionality between your computer and the mixer, allowing you to record and do other fancy stuff.
 
I personally don't use one, so I'm not sure about details on which mixer to get or the best setup for your situation, but I think it would be a good solution.