In April of 2018 I decided to build a top of the line Gaming PC to go along with my new home theater. To that end I ordered the motherboard, CPU, Cooler, RAM, Case, Power Supply, 3x NVME SSD, SLI Bridge, PSU Cable Set, PowerLinks, and Windows 10 Pro.
The rest of the parts including the 2 video cards were taken from my existing system.
Simultaneous to this I purchased my home theater components which consisted of a LG 77" 4K OLED (since upgraded), Denon X8500 AVR, and a 7.1.4 Speaker System.
The home theater also includes: PlayStation 4 Pro with PS VR, Oppo UDP-203 4K Ultra HD Blu-ray Disc Player, Nvidia SHIELD (2017), Apple TV 4K, Sony FMP-X10 4K Media Player, PlayStation (original) (these are not on the parts list)
The first major upgrade was in October 2019 when I became the first in the USA to take delivery of the LG 88" 8K OLED. It is G-Sync compatible and has HDMI 2.1 input capable of 4K 120Hz and 8K 60Hz.
The Valve Index was purchased in November 2019.
I am planning to upgrade the video cards in 2020. I do not foresee the need to upgrade any other parts for many years.
All games are running at 4K 60Hz with maximum settings. Hopefully the next generation video cards will have HDMI 2.1 allowing for 4K 120Hz output.