Thanks for the education Zoid! Puts my mind at ease that you mentioned NVIDIA and AMD because that is what we're leaning towards. I've also read that a large investment is in the GPU and that's understandable. We decided on 1440p, and after doing independent research, came up with the same GPU.
You're on the right track!
I think 1440p is the sweet spot right now for PC gaming. It's better than 1080p while still be attainable at sane price points.
Do look at an adaptive sync monitor. VESA Adaptive-Sync (branded as AMD Freesync) or NVIDIA G-Sync depending on the GPU you get. This will allow you much more flexibility with framerate without having to worry about screen tearing.
GPU: PNY - NVIDIA GeForce RTX 2060 SUPER 8GB
As for which GPU to buy, @Boon72
's observation that we have a new generation of GPUs releasing over the new couple months (NVIDIA RTX 3000 series and AMD Big Navi) is correct, and they are set to offer a nice boost in performance. But while it's true that the RTX 2060 Super is going to be superseded soon, the RTX 3060 hasn't released yet, and will probably experience the same issues with supply that its big brothers have. The bottom line is - wait a couple months if you can, otherwise get the best deal you can now and start gaming
before making your decision, do check out the Radeon 5700XT, which can offer 2060 Super or better performance for slightly cheaper.
As far as a motherboard and cpu, what do you think? I'm not familiar with brands, but my research tells me to choose an AM4 socket (cheaper than intel).
Mobo: Either MSI B550 Tomahawk Gen 2 or Amazon has a Gigabyte x570 Aorus Elite
CPU: AMD Ryzen 5 3600 3rd Gen
Anything I can substitute to bring the price down? Am I able to use my existing Mobo and CPU with this GPU?
In the interest of mitigating the initial expense, I'd say start with just the GPU. A new GPU will plug right into your old system and work just fine. The i7-3820 may be getting on in age but it can still throw some punches, so you might decide it's all you need for now.
If you do decide that the i7-3820 is holding you back, you will have waited long enough to get into Zen 3 CPUs (Ryzen 5000 series) which are set to offer a noticeable performance boost over Zen 2 (Ryzen 3000 series) and release next month. The Ryzen 5 5600X will be the one to watch for. Of course in addition to your new CPU and motherboard you'll also need new DDR4 RAM (DDR4-3200 or 3600 is the price / performance sweet spot for Ryzen) since your old DDR3 won't work on the newer platforms.
As for the AM4 platform vs Intel FCLGA1200, you're correct that the motherboards tend to be a little cheaper. It's also (in my opinion) the better platform. It supports PCIe 4.0 (unimportant currently but will be in the future) and enjoys broader compatibility. The AMD Zen processor architecture is also just more modern than Intel's current offerings. Don't get me wrong, Intel is keeping pace, but they've gone from being relatively uncontested for the last decade to being a bit on the back foot.
One more observation about your build - typically I would recommend replacing a power supply after 6+ years for peace of mind, but that EVGA SuperNOVA is a very good unit, and should have a 10-year warranty still in effect.