St.Nick

I'll chime in with the hydro X part. Especially their Pump/Res combo. It's a D5 so you can use it with other custom loops too but I love that their reservoir is not acrylic and doesn't seem to be quite as susceptible as it is to turning brittle from heat cycles or cracking (because of them).

I think he means the RGB on the front of the case.

Well, the 3000 series does offer better IPC and thus performance. As for why you NEED X570, right now (almost) nobody does. But the keyword is right now, I am honestly just gonna parrot the cause that Jayz champions. The absolute minimum needed for a budget build might seem appealing now, but if your sinking close to a thousand into a system the extra 100~150 bucks that a newer platform costs in the long run will give your system more lifetime. I don't think you need to drop the 'future proofing' buzzword since it's absolutely a marketing trick but even at the low end a slightly higher pricepoint will help keep your system upgradeable.
 
Since AM4 seems to be around for a while longer an x570 board probably will handle the 4000 series too once that hits and better ram has been a trend with Ryzen since then 1000 series. So spending that little bit more now will see you end up with a good board for the next round of processors and maybe even the one after that while the B450 will probably not last another round of upgrades and 3000 mhz memory will just leave processor performance unused right now. And if you want to upgrade it later your gonna have to replace all your ram. Is it  absolutely needed for what you do right now?
 
Probably not and buying what you need right now is totally a good option too and might be fine for your use case. I just felt it deserved a mention that it is an option you could consider. Your workload and wants might chance and leaving yourself upgradeability is never really a bad thing if you see yourself continuing to be a PC user for the forseeable future. Ultimately it's up to you to decide what you want, but being able to see all options and making an informed decision is never a wrong thing imho.

Honestly I'm with Ryan on this one. You could just drop a NH-D15 in there if you're already that invested in Noctua and be fine on air. If it can tame an overclocked FX-9590  the 3950X will be fine too. 

you can, but its still a bit buggy right now. the cheaper board with less features is still rated at tier A on the list by the way. it has a rediculously good vrm setup. it and the asus TUF are this generations major winners in terms of the 200 dollar boards that compete with 400 dollar ones.

We could tell him to get the Àorus Elite that has almost the same VRM setup (and an exceptional one for its much lower price) and no dual bios shenanigans that are currently plaguing half the people running the aorus master to free up that 170ish bucks?

So, the LMG Lan Center builds tickled my fancy a while back, and now with Zen2 out I figured it was finally time to retire my FX-8350 based build. However since there aren't really any Micro ATX boards available for x570 in my region I couldn't go with the 280x case, instead, I have settled on going with a bigger build in White. 
 
Here is the parts list of what I have decided on. I couldn't exactly afford to buy everything right away but I have started on buying parts piecemeal. I am still waiting for the DDR-4 memory to get shipped out before I can switch in the new Motherboard and CPU. I have also changed quite a few parts just to fit my own preferences and what I had available in my region and with the new platform however the concept of the build is still pretty much there. A x700X series AMD CPU in a Corsair Crystal White Case for an all white build with Corsair for an RGB ecosystem (and RGB Fusion to handle everything else that corsair doesn't make, hence why the GPU and motherboard are both from Gigabyte)
Case 
Corsair Crystal 680X - Purchased Cooling
Corsair Light Loops 120 Black x 3 (3 Front Intake) - Purchased Corsair Light Loops 140 Black x 2 (Top Intake) 1 Noctua NF-A15-HS PWM Chromax (White End Pieces) Rear Exhaust  - Purchased 2 Noctua NF-A15-HS PWM Chromax (White End Pieces) Bottom Intake   Noctua NH-D15  AM4-se - Purchased 1 Noctua NF-A15-HS PWM  (Black End Pieces, Shroud painted white for in the NH-D15  - Purchased 1 Corsair Light Loops 120 White (Swapped the fan pads with the black ones from the rear fan that comes with the 680x, goes on the front of the D15 for RGB!) - Purchased Noctua Chromax White Covers - Purchased RGB & Accesoires
Corsair Commander PRO - Purchased Corsair Lightning Node PRO - Purchased Corsair RGB LED Fan HUB x2 - 1 x Purchased Corsair RGB LED Lighting Kit Pro Power Supply
Sharkoon Silentstorm Icewind 650w - Purchased Motherboard
Gigabyte Aorus X570 Elite - Purchased CPU
AMD Ryzen R7 3700X - Purchased Ram
8 GB Trident Z Neo 3600mhz Cl16 - Purchased M.2 Boot Drives
Kingston A2000 x 2 (Raid 0) Hardrives
Seagate Barracuda 7200 RPM 2 TB x 2 - Purchased GPU 
Gigabyte RTX 2070 Gaming OC 8G White - Purchased  
However it seems like a crying shame to leave all these parts in their box while I wait for memory, so this afternoon I will be building my Crosshair Formula V and FX-8350 into the case to get started and swap out the new parts as they come in. Even so I am very much excited to get this build underway. Pictures will come as soon as I finish this afternoons building session. 

Edit 26-08-2019: So I Swapped around the planned fan setup a little after getting some hands on experience with the case, I didn't want to get a second RGB hub so with a limit of 6 RGB fans on 1 hub taking up RGB slot 2 on on the commander pro and the Lighting node pro with RGB strips going on RGB  slot 1 eventually I should have all RGB on the front and top. two 140's look better on top then 120's so i switched those out to. for bottom intakes I added some more Noctua chromax fans and for the cooler I decided to go very white and painted the hub on one of my brown noctua's white, put the black caps from one of the chromax fans on there and switched the front fan out for a Single white LL120 to get some RGB on there and to make sure I could move it up higher to avoid conflicting with my RAM clearance. 

For the front glass panel, I am not really happy with the airflow that I'm getting from that, so I'm debating removing it in favor of a custom Acryllic piece. Photoshop design for the new front grill should be up shortly.
 

The cheapest X570 board coming out at the zen2 release is going to be around 225~250 MSRP with the premium boards starting at 600 according to the leaks we got today. This chipset is not cheap. Going with a lower end x470 right now is the sane choice if you have a budget at all. By the time PCIE 4 is going to be a real and interesting choice in like 6~9 months when Intel also has boards that support it and the PCIE 4 products actually become available at reasonable prices those x570 boards might have dropped in price enough that you essentially got your X470 board for like 30 or 40 bucks and still end up with the same X570 board you might have been able to buy now (if you deduct the price drop from the purchasing price of an X470 board.) And you save yourself the potential hassle of waiting for firmware upgrades. A new chipset release is almost always gonna have a few weeks or even months of teething issues. Early adopter issues are a real thing to consider. The same is still true for the CPU's themselves though so.. pick your poison?