all of you people got some small mistakes in their opinion, there is no reason to go with X chip unless you 100% want to buy a cooler. if not, the Stock cooler of All ryzen will do the Job, the difference between Ryzen 1700 and 1700x is 150-200Mhz which will cost more for the X chip and more for the cooler.
the Ryzen 1700 can do 3.8 with Stock cooler with a little bit modified Fan curve,
- Ryzen 1700 or Ryzen 2600 ( i prefer the 2700 4.1 or 4.2 Ghz but it costs much more )
- MSI B450 Tomahawk / MSi B450 Pro Carbon, these are the Top best VRM motherboards, in addition of the "B450I Gaming Plus" for Small size.
- 2x8 RAM 3000Mhz if Ryzen first Gen and 3200 or more for the 2nd Gen.
- for SSD i suggest you get 240gb for main drive and another 240g or 500gb for your Data depend of your usage games etc.
- GPU is defenitely RX 580 8gb no question ask, if you can afford more get the gtx 1070 or 1070ti
- 550w PSU, pick a good brand with Bronze certification, your system will use 400-450w even with OC so the 550w is plenty.
- no big idea about monitors brands, but 144Hz 1080p is the way to go. but honestly you need 110+ fps for that 144hz so the RX580 is kinda not enough.