You're probably going to get a lot of different answers and here's what I would buy today:
Asus Crosshair VI Hero - just for the driver support, BIOS and overall abilities. I also like that this board is neutral in colors (I refuse to buy a board if the manufacturer forces me into a particular color scheme). These boards also seem to be the first boards to get critical updates compared to the rest Asus has to offer; all other ROG's and Strix boards follow a few weeks later. It costs a bit more, but I'm willing to pay the extra for faster updates and OC'ing options.
Surely you've looked at boards - what's your pick?
I picked up the ASRock x370 Professional Gaming. This is my first ASRock board for a primary system and I couldn't be happier. I picked it up primarily because it was marked on sale at my local Microcenter for $199.00 plus another $30 off with the purchase of a Ryzen processor. Getting a top end x370 board for an effective $169.00 was too good of a deal to pass up. I don't regret it at all. The 5 Gbps Aquantia Ethernet is a bit wonky at times, and I think it would work better with other 5 Gbps products, if any ever release. You can bypass the questionable utility of the 5 Gbps Ethernet and pick up the x370 Taichi. It seems to be the favorite of overclockers on overclock.net.
ASRock is my second preferred vendor I would try. I almost ended up getting this one since the Crosshairs were out of stock, but quickly emptied NewEgg as soon as they were announced back in stock later that day. ASRock was a bit rough around the edges in their early days, but they've come a long way since then! Especially in the consumer market. I wonder why they started with the early >1Gb Nic adaptations on consumer products? I can see if there were NAS, Cam etc appliances widely available, but they just somewhat popped up everywhere.
I suppose it is nice just including a second Ethernet port. Aquantia sells the AQN108 as an add in card for $100, so getting the chip included in the motherboard is a nice savings. However, there doesn't seem to be any consumer 2.5/5Gbps network infrastructure products available. No switches, routers, nothing. Even the router ASRock themselves produces doesn't include it, which seem strange. It would be nice to have for gaming streaming and piping mkvs around the house.
ASRock has been very quick with UEFI updates, and I'm happy with the overclock I have been able to get and just the overall stability of the board. I have used ASRock boards in the past, but both were mITX, APU builds (One Kaveri, one Llano based) that were used for media consumption and light computing. With both builds are still in use today I was pretty confident the ASRock board would last problem free.
My initial plan was to pick up the MSI XPower Titanium or ASUS C6H, but like I said, $169.00 for the ASRock board was a great deal and the board has been excellent.
it really depends on what you plan on needing and what brand you trust. i am usinth the b350m gaming pro from msi and i have yet to have any problems and it has all the fetures i need. i plan on geting the x370 carbon from msi eventually for higher overclocking but its are really good board otherwise
gigabyte GA-X370-GAMING K7 and 5 have 2 ethernet nics, Intel+Killer and no wifi. Gigabyte and Asus have beta Bios available that is a plus.