2020: Time for a new desktop

[Moonlight]

You haven't said what your price range is for this new machine or even what you're going to be doing with it so we'll start with the CPU and then you can get the rest to fit around it.
As you're on a games website I'll give you 4 CPU optons for you to mull over, if these are too much for your wallet I would have a look for some mid range CPU's.

Most powerful gaming CPU: Intel Core i9-9900K Intel thinks Onkel Neal is rich.
This is really only recommended for serious gamers.

Best value gaming CPU: Intel Core i7-8700K In your dreams baby.
A better value proposition with only a slightly worse gaming performance than the Intel Core i9.

Most versatile gaming processor: AMD Ryzen 3900X Not as pricey as the 2 above.
If you’re regularly dipping into multimedia editing tasks this is the one to buy due to its superior core and thread count.

Best budget gaming CPU: AMD Ryzen 7 2700X I'd start here first and work my way up.
for those on a budget, or for those who are sensible about their wallets feelings.