In order of preference, I'd go ASUS Maximus Hero VIII, Gaming 7, Z170-A and then Gaming K3. All are good boards, but you get what you pay for, as with most things, however the Z170-A has features you usually only find on much higher end ROG boards, so for the price, if you don't mind the plain aesthetics, it's a really good choice.
Only problem with that board really is the fact that the style of IO shield it uses makes it fairly hard to install, as it tries to get in the way and not go where it needs to during the installation. I saw this before ever doing a build with one, ignored it, and found it to be true after all.
It's still a value segment motherboard : I might be nitpicking, but there are some parts of the board I feel could be better, and that is probably due to the board's low price point. The first is the IO shield that has huge hanging grounding fins that make it hard to install. The fins that stick out can easily slip into a slot, and they did, I had to mount the board twice with multiple tries to get it right. There are also only three LEDs that illuminate the PCB divide, which doesn't provide great illumination; you have to kind of stick your head in the case to see the lighting.
Read more:
https://www.tweaktown.com/reviews/7506/asus-z170-intel-motherboard-review/index11.html
It does have M.2 though, which is nice on a budget board. It also has Intel NIC, which again is normally not found on budget boards because ASUS has to pay a premium to include this on any boards it wishes to use it on.
It also has a very good UEFI bios interface. All of this is mentioned in the review at the link above, but I can verify it all to be accurate based on my own experience with this board.
My short list of choices when building with Skylake, and not going overboard to an extreme model, would easily be limited to the Gigabyte Z170x-gaming 3, gaming 5 and gaming 7, the ASUS Z170-A and the ASUS Maximus VIII Hero. All have the features you wanted, all are very reliable and are built using high quality components and all are fairly reasonably priced. These boards are solid choices.
The only problem with the Gaming 3 and SFAIK the K3, is that they are limited by the exclusion of a few perks like additional fan headers, slightly worse performing/vanilla flavored network controllers, etc.
One thing possibly worth mentioning is that the Gaming 3 has a U.2 slot in addition to an M.2 slot, which, unless I'm mistaken, means this board could potentially support the new Intel Optane memory drives, but I'd have to look into that further to verify. Pretty sure they are mainly U.2 compliant though. For mixed workloads, the Optane drives are very compelling but they are also very expensive compared to M.2 NVME drives like the Samsung 960 Evo and Pro. I'm definitely adding one of those fairly soon if at all possible.