Looking for Feedback on My First Z170 Gaming Build

I am getting ready to order parts to build my first gaming PC. This is the first time I have ever built a PC. I plan to use it primarily for gaming (CS:GO, Arma 3, GTA V, Battlefield 4, Star Wars Battlefront, Rainbow Six Siege, The Division, The Witcher 3, Doom, Fallout 4, Homefront, Squad, Overwatch, WoW, etc.), preferably at max. settings. I will probably upgrade and expand on this build as necessary. I also plan on overclocking at some point. I am also considering SLI, multiple monitors (possibly at least one 4K), and VR sometime in the future. I'm also considering maybe streaming or doing some Let's Plays as well.

Here is my parts list for reference, with some of my questions/concerns below it:

[PCPartPicker part list](http://pcpartpicker.com/p/xdrZ4D) / [Price breakdown by merchant](http://pcpartpicker.com/p/xdrZ4D/by_merchant/)

Type|Item|Price
:----|:----|:----
**CPU** | [Intel Core i5-6600K 3.5GHz Quad-Core Processor](http://pcpartpicker.com/part/intel-cpu-bx80662i56600k) | $240.31 @ Amazon
**CPU Cooler** | [Cooler Master Hyper 212 EVO 82.9 CFM Sleeve Bearing CPU Cooler](http://pcpartpicker.com/part/cooler-master-cpu-cooler-rr212e20pkr2) | Purchased For $0.00
**Motherboard** | [Gigabyte GA-Z170X-Gaming 7 ATX LGA1151 Motherboard](http://pcpartpicker.com/part/gigabyte-motherboard-gaz170xgaming7) | $199.95 @ Amazon
**Memory** | [Corsair Vengeance LPX 16GB (2 x 8GB) DDR4-2666 Memory](http://pcpartpicker.com/part/corsair-memory-cmk16gx4m2a2666c16r) | $74.99 @ Newegg
**Storage** | [Samsung 850 Pro Series 512GB 2.5" Solid State Drive](http://pcpartpicker.com/part/samsung-internal-hard-drive-mz7ke512bw) | $223.35 @ Amazon
**Storage** | [Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive](http://pcpartpicker.com/part/western-digital-internal-hard-drive-wd10ezex) | $53.99 @ Amazon
**Video Card** | [EVGA GeForce GTX 980 Ti 6GB ACX 2.0+ Video Card](http://pcpartpicker.com/part/evga-video-card-06gp44991kr) | $649.99 @ Amazon
**Case** | [Cooler Master HAF X ATX Full Tower Case](http://pcpartpicker.com/part/cooler-master-case-rc942kkn1) | Purchased For $0.00
**Power Supply** | [EVGA SuperNOVA P2 850W 80+ Platinum Certified Fully-Modular ATX Power Supply](http://pcpartpicker.com/part/evga-power-supply-220p20850x1) | $134.99 @ Amazon
**Optical Drive** | [Asus DRW-24B1ST/BLK/B/AS DVD/CD Writer](http://pcpartpicker.com/part/asus-optical-drive-drw24b1stblkbas) | $19.99 @ Newegg
**Operating System** | [Microsoft Windows 10 Home Full - USB (32/64-bit)](http://pcpartpicker.com/part/microsoft-os-kw900016) | Purchased For $0.00
**Monitor** | [AOC G2460PG 144Hz 24.0" Monitor](http://pcpartpicker.com/part/aoc-monitor-g2460pg) | Purchased For $0.00
**Keyboard** | [Corsair K70 RGB Wired Gaming Keyboard](http://pcpartpicker.com/part/corsair-keyboard-ch9000068na) | Purchased For $0.00
**Mouse** | [Logitech G502 Wired Optical Mouse](http://pcpartpicker.com/part/logitech-mouse-910004074) | Purchased For $0.00
**Headphones** | [Kingston HyperX Cloud II 7.1 Channel Headset](http://pcpartpicker.com/part/kingston-headphones-khxhscprd) | Purchased For $0.00
**Speakers** | [Logitech Z313 25W 2.1ch Speakers](http://pcpartpicker.com/part/logitech-speakers-980000382) | Purchased For $0.00
| *Prices include shipping, taxes, rebates, and discounts* |
| **Total** | **$1597.56**
| Generated by [PCPartPicker](http://pcpartpicker.com) 2016-05-04 14:52 EDT-0400 |

After doing a lot of reading on motherboards, I feel that Gigabyte is probably my best bet. I just don't feel comfortable taking a chance with possibly having to deal with ASUS tech support or finding out for myself if MSI's quality control is as bad as some say it is. I currently have my eye on the board I have included in my parts list. If anyone feels there is a better board they can recommend, and why I should get that board instead, please feel free to let me know.

I am also not entirely sure about which graphics card I want yet. I know for sure I want some version of the model included in my parts list. I just don't know if I should go with a factory overclocked version or a non-overclocked card. Feel free to give your opinion on this matter. If I choose an overclocked card, will I need to buy more fans or a better power supply?

Should I stick with the i5 in my parts list? Or should I get an i7 instead/upgrade to one later on?

Is my PSU enough for my purposes? Or should I get a bigger or smaller one?

If there is anything else I have overlooked, please let me know. Sorry if this is a lot of questions. I am just trying to learn as much as I can and make sure my build goes as smoothly as possible.

Thanks!