TechChild

The major difference is multiple users accessing the system simultaneously. Hence why I said to ask about anticipated growth in access to this machine as that will inform the spec decisions to keep the system in service as long as possible - generally 5 years is the anticipated lifespan of a server or desktop for SMB and enterprise.
 
Beyond that, the specifications are also going to depend substantially on what that server is doing. Anyone can look up system requirements for software, but unless you have recommendations based on your use case, that doesn't really tell you much. For example, a Raspberry Pi can be a great server option for light duty and proof-of-concept. But it'll choke if you try to use it to host a website being hit by a significant number of clients simultaneously. That's why servers tend to have much beefier specs compared to desktops, or are multiple nodes behind a load balancer.
 
And the other major difference between a desktop and server: downtime must be kept as close to zero as possible. Hence the recommendation against going DIY. Prebuilt systems are inspected prior to shipment, and servers are even more closely inspected to ensure the chance of failure after they've been put into service is as close to zero as possible. The manufacturers are also in a much better position to anticipate and account for the one-off dead piece of hardware that could cost you (and your employer) hours or days of time replacing, not to mention any downtime should that part fail after you put the system into service.
 
That was supposed to be that you have no experience spec'ing a server, let alone building one.

HP, DELL etc.  The big names have lots of options for servers at all levels of performance with the kind of support you need.

It's actually not a bad idea to buy a prebuilt-one, because you get warranty and various kinds of support-options. I mean, it's used for making money, so any time wasted on you trying to fiddle with the hardware should something go wrong is money lost. I would only suggest going the DIY-route if you are already exceedingly familiar with DIY-builds and you are sure you can fix any issues faster than the folks behind a prebuilt, brand-name one could.

Okay, time for some educating. I would really like some help and recommendations.
 
I have been out of the home-built PC world for a long time. The last one I built was when I was in Middle School (a little over 12 years ago now) and even when I was "super into it" i didn't really have a budget to work with (I modded my parent's old computer that they donated to me). I learned how to match RAM and the limitations of the motherboard, and what CPU would work with it and then I scrounged around for a graphics card.
 
But, I was never really in a position to build anything with the raw strength to power through high end games. I was always stuck with Warcraft 2 and Star Wars X-Wing vs. Tie-Fighter. (which were great games btw, especially X-Wing vs. Tie Fighter).
 
So, I need some education on several things. What should I be looking for with my motherboard and CPU now in 2018. I am looking at building a new PC and making my own tower for it, custom built to my specifications (going to put it into a desk with a glass top so that I can house my PC somewhere other than the floor. And I am going to style it so that it looks beautiful, with water-cooling and RGB, you get the picture. But I don't know what components really to be looking at or considering. I know that Intel just released it's new processor (and it looks like it kicks butt). However, I don't know what motherboards are great currently that can truly harness that CPU. I don't know what to do with Graphics. I use multiple monitors, and would really like a build that could play well with 3, possibly even 4 monitors. (I recently started doing some hobby web design, and found out how beautiful it was to have more display real estate).
 
So any suggestions would be really great. Especially with opinions about the current graphics card arena, motherboard, CPU. 
 
This is my goal with this PC: create something that can run any high end game at 60+ fps. Ideally without spending more than $5,000 on parts. But, the goal is performance, not price. I want quality, and you can't have really good quality without shelling out some cash for it.
 
Anyways, Please let me know!