If you go for a overclock AND the GTX 1080 I'd definitely opt for the 650Watt power supply.
As things stand the builds linked are actually similar in overall performance, the i5 8600K/GTX1080 will be a little faster in games while a i7 7700K/GTX1070Ti would be a little better as an all round system-if you regularly do things like video encode or render it'll be quicker there.
Here's a rebalanced i7 7700K build with faster memory, a GTX 1080 and the 650Watt PSU, to save a little cash, though I've dropped to a cheaper 256Gb SSD and a less expensive motherboard:
PCPartPicker part list /
Price breakdown by merchant
CPU: Intel - Core i7-7700K 4.2GHz Quad-Core Processor ($374.99 @ Amazon Canada)
CPU Cooler: CRYORIG - H7 49.0 CFM CPU Cooler ($46.75 @ Newegg Canada Marketplace)
Motherboard: ASRock - Z270 Killer SLI ATX LGA1151 Motherboard ($138.50 @ Vuugo)
Memory: Corsair - Vengeance RGB 16GB (2 x 8GB) DDR4-3600 Memory ($287.44 @ Amazon Canada)
Storage: SanDisk - SSD PLUS 240GB 2.5" Solid State Drive ($105.75 @ Amazon Canada)
Storage: Western Digital - Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive ($54.75 @ Vuugo)
Video Card: EVGA - GeForce GTX 1080 8GB FTW DT GAMING Video Card ($694.46 @ Newegg Canada)
Case: Cooler Master - MasterBox Lite 5 RGB ATX Mid Tower Case ($86.36 @ Amazon Canada)
Power Supply: SeaSonic - FOCUS Plus Gold 650W 80+ Gold Certified Fully-Modular ATX Power Supply ($119.99 @ Newegg Canada)
Total: $1908.99
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2017-12-21 05:12 EST-0500
Again, open to discussion or tweaking.
Also, Dabrony, can you tell us what the system is going to be used for? If gaming what display/s will you use or what do you intend to use? It's important to balance the whole system, pairing any of the above builds with a 60Hz HD display will be a waste of money for example but if you regularly do a lot of rendering that is CPU intensive you'll be better off with a 8 core Ryzen build, maybe sacrificing a little gaming performance to gain some rendering muscle.