Rate this build pls!

Running games on max settings depends on which resolution you're playing.

At 1080p, you'll do fine with GTX 1060/ RX 580.
At 1440p (2K), you'll need GTX 1070 / RX Vega 56.
And at 4K, you'll need GTX 1080/ RX Vega 64.
For best performance at 4K, GTX 1080 Ti is best used.

As far as your list goes and because you asked for rating, here's how i'd rate your picked components with reasons why,
CPU - 5/5 - i7-7700K is best currently offered by Intel and for gaming alone, it's best CPU to go for.

CPU cooler - 2/5 - Single slot AIOs have such a poor performance that they are outperformed by most air coolers. Single slot AIOs are meant for small ITX builds where there's not enough CPU cooler clearance for proper air cooler.

MoBo - 3/5 - While there are better MoBos out there (more features/eyecandy), your picked MoBo will do fine, despite being on the cheap end of Z270 chipset MoBos.

RAM - 3/5 - With Z-series MoBo, you can use much faster RAM than stock speeds of 2133/2400 Mhz. While 2666 Mhz is a bit better than stock speeds, the most optimal RAM speed would be 3200 Mhz.

SSD - 5/5 - Samsung 850 Evo is best performing SSD in 250GB range and it's a great choice.

HDD - 5/5 - In 1TB range, WD Blue is solid HDD to go for. I have 4x 1TB WD Blue HDDs in use in my household.

GPU - 5/5 - For 4K gaming with ultra settings, GTX 1080 Ti is best choice.

Case - 5/5 - Corsair 760T is one of the best (if not the best) full-tower ATX case. Build quality vise, Phanteks Enthoo Pro would be on par with 760T. My Skylake build also sits in 760T. Full specs with pics in my sig.

PSU - 4/5 - While EVGA Supernova 550 G3 PSU is a good choice, there are better PSUs out there.

I also refined your build a bit.

PCPartPicker part list / Price breakdown by merchant

CPU: Intel - Core i7-7700K 4.2GHz Quad-Core Processor ($306.89 @ Amazon)
CPU Cooler: be quiet! - Dark Rock Pro 3 67.8 CFM Fluid Dynamic Bearing CPU Cooler ($83.78 @ OutletPC)
Motherboard: MSI - Z270 GAMING M5 ATX LGA1151 Motherboard ($169.99 @ Amazon)
Memory: Corsair - Vengeance LPX 16GB (2 x 8GB) DDR4-3000 Memory ($147.99 @ Amazon)
Storage: Samsung - 850 EVO-Series 250GB 2.5" Solid State Drive ($104.64 @ OutletPC)
Storage: Western Digital - Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($46.88 @ OutletPC)
Video Card: MSI - GeForce GTX 1080 8GB GAMING X 8G Video Card ($599.88 @ OutletPC)
Case: Corsair - 760T Black ATX Full Tower Case ($149.99 @ Amazon)
Power Supply: SeaSonic - FOCUS Plus Gold 650W 80+ Gold Certified Fully-Modular ATX Power Supply ($89.90 @ Amazon)
Operating System: Microsoft - Windows 10 Home OEM 64-bit ($92.99 @ B&H)
Total: $1792.93
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-08-20 02:43 EDT-0400

Few words

As i said above, single slot AIOs have poor performance. So, replaced CPU cooler with one of the best big air coolers that has nice black theme.
review: http://www.tomshardware.com/reviews/be-quiet-dark-rock-pro-3-cpu-cooler,4350.html

I also replaced your MoBo with a better one. Feel free to switch it back to save some money,
review: http://www.tomshardware.com/reviews/msi-z270-gaming-m5-intel-kaby-lake-atx-motherboard,4873.html

While 3200 Mhz RAM is most optimal for gaming build, it's also quite expensive. So, made a compromise and put in 3000 Mhz normal-profile RAM. Since Be Quiet! Dark Rock Pro 3 has RAM clearance of 40mm, your picked G.Skill RAM is too high for it (42mm), while Corsair LPX fits under it just fine (33.5mm). Just install RAM before installing CPU cooler, it's easier this way.

Since you wanted a cheaper GPU than your Asus GTX 1080 Ti, i replaced it with MSI GTX 1080 Gaming X GPU. While GTX 1080 isn't as powerful as GTX 1080 Ti, you still can game on 4K fine. Also, GTX 1080 has better performance than GTX 1070,
comparison: http://gpu.userbenchmark.com/Compare/Nvidia-GTX-1070-vs-Nvidia-GTX-1080/3609vs3603

I also switched out your PSU without any additional cost but with extra 100W output. Since you're probably going to OC your CPU/GPU, extra 100W of output power comes handy. Extra wattage isn't only gain, you'll also gain 3 years longer warranty period with Seasonic Focus+ 650. While EVGA G3 has 7 years of warranty, Seasonic Focus+ has 10 years of warranty.
Though, my 1st choice of PSU replacement was Seasonic PRIME 650 80+ Titanium since it's the best 650W PSU money can buy at current date. But since it also costs accordingly, i went with Focus+ instead. My Skylake build is powered by Seasonic PRIME 650 80+ Titanium though.