I custom built a PC on HP's website 9 years ago and it finally died. I'm computer literate but by no means an expert. I felt that building my own PC would be beneficial so I did just that. I knew very little about all the brands and styles for each component so I began this whole endeavor mostly by googling "Best CPU/motherboard/GPU/etc 2019." Adding "reddit" to my searches helped a lot too. PCPartPicker, as well as everyone posting their builds and product reviews, was a massive help so I wanted to give back and make my own post. I built my computer on 9/8/2019. If you have any questions feel free to ask (if you even can. I just registered an account so I don't know how it works yet) and I'll be happy to help.
CPU: I went AMD over Intel for a couple of reasons. AMD was cheaper and they have been using the same motherboard socket for a while now. I liked that they weren't forcing you to buy a new MOBO every time you wanted to upgrade you CPU. I was initially going to go with the Ryzen 5 3600 but in my research I found that it has a lot of BIOS issues with B450 MOBOs. Jumping up to an x570 MOBO was starting to strain my budget so I went the other way. I got the Ryzen 5 2600x over the 2600 simply because it was only $13 more. More performance and a better stock cooler for $13 was a no-brainer to me.
CPU Cooler: The internet seems to agree that the stock cooler for the 2600x is adequate so I didn't buy one. I can always buy one later if I wanted to and if I did, I would probably get the Noctua NH-D15S or the Cooler Master Hyper 212 Black Edition 42 CFM if I wanted to save money.
Motherboard: I went with an ATX MOBO because I had no reason to go smaller. Plus I wanted room to work and didn't want to be cramped. The MSI B450 Tomahawk is the highest rated MOBO out there but from what I read, the B450-A Pro is nearly the same thing without RGB controls. I don't care about RGB so I went with the B450-A Pro to save some money. I did not update the BIOS. MSI even says not to on the drivers page of their website. I've had no issues with the MOBO or CPU so that was a wise decision on my part.
Memory: Internet research said that Ryzen CPUs like faster RAM and the G.Skill Ripjaws V Series were mentioned a lot. I liked the price point so that's where I went.
Storage: I went with the Crucial MX500 1 TB M.2-2280 SSD mostly because that's what popped up when I googled "best SSDs 2019." This wound up being the only problem I had with my install. My computer recognized the drive but every time I tried to format it it would fail. I wound up going to Crucial's website, clicking on the correct page for my SSD, and downloading their firmware. I tried formatting again and it worked.
I also had a 1 TB Western Digital HDD from my old HP and a Samsung SATA SSD that I added to that a couple years ago. Honestly, if I were to rebuy everything, I would go for a Western Digital 1 TB M.2-2280 SSD instead of the Crucial MX500. Mostly because their 9 year old HDD is still alive and kicking (I like to reward well made parts with loyalty) and they're a brand I've heard of before. The only problem is I didn't know my HDD was a Western Digital until I took it out of my old PC after I had already bought all my new components. To be fair, I haven't had any issues with the Crucial thus far though besides having to download firmware to get my computer to format it.
UPDATE: I wrote this during the day and literally that night I had more problems. I wanted to create a system image backup. Apparently you can't do that on a flash drive? So I figured I'd put it on my Crucial M.2. Big mistake. It made it 99% of the way and failed. Then it wouldn't let me reformat. Then my computer wouldn't recognize it at all. I took it out completely. Put it back in. The computer recognized it and even let me reformat it. The reformatting froze. I restarted the computer but I was lucky if I could even see the little motherboard logo during boot up. It wouldn't post at all. Pulled the M.2 out and it booted up no problem. I don't know what the issue is. Maybe M.2 is still a bit new and there are some early adopter bugs? Regardless, I don't have the patience for this so I returned it. I didn't want to write off Crucial completely as the internet holds them in high regard. I bought the same exact SSD but in the 2.5" form factor. I'll update again once that gets here and I install it. I have a 2.5" Samsung 850 which has worked perfectly so hopefully my Crucial will too.
UPDATE PART 2: My Crucial MX500 1 TB 2.5" SSD came today. I hooked it all up, did the formatting (new simple volume) thing again and it worked the first time perfectly. So I can't say what my problem was with the M.2. Maybe I needed to update the BIOS but I mentioned in the motherboard section above why I didn't want to do that. Maybe my motherboard wasn't high end enough for M.2 drives. Maybe I had a bad M.2 drive. I don't know. Ultimately, I don't care. My 2.5" SSD works and I'll be set for years.
Video Card: I was leaning towards the RTX 2060 but in the interest of cost savings, I went with the GTX 1660 Ti. Numerous YouTube videos with my CPU and GPU showed that they could play even the most demanding games at a high FPS so I'm not worried about performance. It helps that I only have a 1080p monitor. I got that when I got my HP 9 years ago. When that dies, I'll be going with a 4K monitor. Unfortunately, that will probably mean having to go buy a new GPU and maybe a new CPU.
I bought the MSI Armor OC version mostly due to price. It was something like $30 cheaper than their Ventus XS OC (although its more expensive now) and if I recall, had better cooling.
Case: I was a hair's breadth away from buying the Corsair 750D full tower but the price jumped up $20. I don't know why but that angered me enough to reevaluate the whole thing and I wound up buying the Fractal Design Meshify C mid tower. I thought I'd need a full tower but these mid towers are plenty big enough, even with 2 SSDs and 1 HDD. The Meshify C is really nice. Its almost all metal, has slots everywhere for good cable management, and it looks cool too. Right now I'm using the stock fans in their stock configuration. If temperatures or dust gets to be too much, I'll be buying two 140mm fans for the front and moving the stock front fan to the top.
Power Supply: SeaSonic came up often in my "best power supply 2019" google searches. I was going to get the FOCUS plus but then I read on a Linus Tech Tips post that there were some issues with that line of PSUs so I went up to the next level and got a PRIME. I went with gold because it seemed like there were diminishing returns the higher you went (platinum/titanium). A PSU calculator I used said that 550 Watts would be plenty but I allowed my friends to talk me into 650 Watts. The fully modular is nice for cable management. You can plug in what you need and leave the rest in the box. I didn't know it has a hybrid mode which only has the fan run when it goes past 40% load I believe. Normal mode has the fan on all the time. Which one you use dictates whether or not you have the fan facing up or down. I decided to use the hybrid mode and have the fan facing up. Its easy enough to change if need be.
And that's my build. Researching all this was a massive pain and quite stressful but I'm glad I built my own PC.
This is the first case I've ever built a PC in but its a great one. It had great reviews all over the internet so I picked it up. Great build quality (mostly metal), easy to build in (lots of cut out slots), and its well ventilated so cooling shouldn't be a problem.
If you're considering a full tower because you think you'll need the space, don't worry about it. I was going back and forth myself but I had zero issues with space in the Meshify C. I have a M.2 SSD, a SATA SSD, and a SATA HDD in there and there's still tons of room. Just make sure your CPU cooler and video card will fit.