If you don't planning on running multi-GPU setup then go for GTX 1060 6GB. If you plan on running more than one GPU then go for RX 480 8GB. I wouldn't recommend Crossfire-ing mid range cards though. It's always better to get a stronger single GPU.

It doesn't matter whether you get ASUS or MSI (it's up to you which brand you prefer and which card fits your build's color theme more). It's the same GPU the only difference is the cooler/heatsink. Both perform great. You can't go wrong with either one.

If you plan on going with AMD then you might want to get a refresh of RX 480 which is RX 580 (it's the same GPU which comes with a little bit higher core clock).

I really like that Tempered Glass case and really digging the white theme with custom loop, looks sweet. I just wouldn't recommend multi-GPU setup. You would have been better off with a single GTX 1080 Ti. But either way that beast will run all of your games on Ultra settings @ 1440p as well as 4K.
I hope you're gonna be doing a lot more than just gaming since this build will tear through everything whether it's gaming or productivity.
BTW nice choice in components. My best friend got that same 570X Tempered Glass Case (few months back) and it looks so good in person. Enjoy your new beast :p

7700K will be good for the next 3+ years. It performs better in games than Ryzen CPU's. Why would he need R7 1800X? That's way overkill and waste of money IMO. If anything he should get R7 1700 which will perform nearly the same for much cheaper. Also why would he need 32GB of RAM? 16GB kit will do just fine for years to come. He's looking more into a gaming build rather than productivity (even then R7 1700 will get the job done at both gaming and productivity for $180 less). On top of that $100 won't be enough for a $500 monitor that he's looking to get.
Builds I made for him leave him $600+ room for a monitor he's looking to get.
I own a 6700K myself which is basically 7700K, I use it for gaming, video editing/rendering and it gets the job done just fine.

You're right and I definitely would not spend $600+ on a CPU. That's already pushing... I usually don't spend over $350 on a CPU.

Our cards are pretty similar then (even looks wise). Highest I've seen my card hit is 69C as well. No need to OC that 1080 Ti beast for now. It already tears through everything. You game @ 1440p, right? You should have no problems what's so ever maxing out all games for a WHILE! :p

This! If you get a decent CPU then all you'll have to upgrade down the road is a GPU. CPU's usually hold up pretty well (decent ones).

Must play games IMO
Shooters: Doom, Battlefield 1, Gears of War 4, Metro 2033 Redux, Metro Last Light Redux, Grand Theft Auto V
RPG: The Witcher 3, Fallout 4, Mass Effect Andromeda
Racing: Forza Horizon 3, Forza Motorsport 6 Apex, Assetto Corsa, Project Cars, DiRT Rally
Games you might like: Titanfall 2, Far Cry 4, Far Cry Primal (assuming you played Far Cry 3), Borderlands Pre-Sequel, Dying Light, Rainbow Six Siege, Wolfenstein The New Order, Mafia 3, Just Cause 3, Rocket League, Need For Speed 2015

No worries. I've had my AMP Extreme 1080 for 7 months now so I've had enough time to play with it and push it as far as it can go.

I'd like to see a 1080 Ti hit 2.1GHz stable.

What kinda temps are you getting under full load with your AMP Extreme 1080 Ti? And what do you think about build quality of the card? It looks very similar to my card... prolly just as heavy and I'm guessing it sags as well? I had to get a bracket support for mine.

If there's a gaming Volta card that was so powerful... well... I'd have to sell my 1080 and buy it along with a new 4K monitor :p

You're funny, I totally came here to bullshit you... right? Not every card is the same, you know? On top of that GTX 1080 overclocks better than 1080 Ti. My card out of the box boosts to 2025mhz.

Take a look at my GPU core clock - http://www.3dmark.com/3dm/16414046