OK, Here's my 2 pennies worth.
Feel free to criticise or reject, I don't care.
Large case with at least 3 front/bottom min size 140mm fans, so internal pressure stops "clagg" being sucked through panel gaps etc.
Kaby Lake 'K' CPU, Quad core but Duo will work for most games. Not necessarily highest clock speed. I need evidence before going to AMD.
Full size motherboard with 4 RAM slots, min of 2 PCIe slots and M" drive connector or two.
RAM 2 x 8GByte DDR4.
ASUS Strix 1080, so GPU temp can be used to control fan speed for 2 of the input fans. Could be paired with a 2nd one in SLI mode.
M2 drive for 'Boot' and most important programs (ED in this case)
SSD for all secondary program executables and program data
Internal HDD for storage of current files.
External HDD for storage of all those things you cannot throw out.
Several memory sticks for installation files, backups and copies of important program installation executables with copies of all those different passwords etc. you have used.
Monitor wide screen 21:9, curved or flat is your choice, you can never have too much real estate. I personally would not go 4K.
Warthog HOTAS with pedals, at moment none of the other designs are convincing.
Keyboard and mouse I consider are very personal choices. What works for me doesn't for my 2 sons (thirty somethings) and vice versa.