PCpartpicker is down where I am located, but I would go with the 2600x, b450 motherboard, 16gb (3200mhz) RAM, GTX 1080, Crucial MX500 SSD, and a quality PSU from Corsair, EVGA, or Seasonic.
The 2600x gets 5% fewer fps than the 8400 and 7% fewer fps than the 8600k.
https://www.techpowerup.com/reviews/AMD/Ryzen_7_2700X/13.html
Yet the 2600x comes with twice the number of threads which will really help with streaming and multitasking.
Then just get the best GPU you can afford and you cant go wrong.
pcpartpicker is back up, I would go with this.
PCPartPicker part list:
https://pcpartpicker.com/list/sKwGnH
Price breakdown by merchant: https://pcpartpicker.com/list/sKwGnH/by_merchant/
CPU: AMD - Ryzen 5 2600X 3.6GHz 6-Core Processor ($225.79 @ OutletPC)
Motherboard: ASRock - B450 Pro4 ATX AM4 Motherboard ($91.98 @ Newegg)
Memory: G.Skill - Ripjaws V Series 16GB (2 x 8GB) DDR4-3200 Memory ($149.99 @ Newegg)
Storage: Inland - Professional 120GB 2.5" Solid State Drive ($24.99 @ Amazon)
Video Card: EVGA - GeForce GTX 1070 Ti 8GB SC GAMING ACX 3.0 Black Edition Video Card ($429.99 @ Amazon)
Case: Deepcool - TESSERACT SW ATX Mid Tower Case ($33.99 @ SuperBiiz)
Power Supply: Corsair - TXM Gold 650W 80+ Gold Certified Semi-Modular ATX Power Supply ($54.98 @ Newegg)
Total: $1011.71
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-08-08 16:59 EDT-0400