I just finished building a machine to use as a backup for my old system. I am running Linux to support Mythtv, Plex and my RSS applicaton. I have used this machine to edit recordings to remove commercials, and to change the encoding of the recordings to reduce the space required.
We have become dependent on Mythtv being available, so I needed a way to test upgrades without risking the scheduled recordings. I also wanted to use virtual machines so I could test new software while still keeping the main system available as a backup.
Although I spent a lot of time analyzing the various motherboards available, I ended up buying an ASRock Z170 Pro4S because it was on sale at close to half price. I learned a few things along the way.
First, the performance improvement for the new Kaby Lake processors is estimated to be 5-10%. This was not enough of an improvement for me to justify going with it, so Z170 was good enough for me. If you go with the Z270 chipset, it gives you the option to overclock the processor if you pay for an unlocked processor. If you are going to overclock, then you may have to consider additional CPU cooling. Make sure your existing case can support this, even if it is just having enough clearance for a bigger CPU cooler. If you aren't going to overclock, then you can save some money by going with the H270 chipset and a locked processor. I went with a Core i5 6500 and it seems to meet all my needs.
One thing I learned was that even though called an ATX board, this board and some others are actually smaller than the ATX standard. The ATX standard calls for a 9.25 inch dimension, and this board was only 8.5". This meant that one row of mounting screws was not available. I find that the front of the board is not as well supported as I would like when plugging in the 24-pin power connector and installing the memory. Definitely install the processor and the memory while the board is out of the case, as it is easier to do on a solid surface.
I went with the onboard graphics, although I put in a power supply that would support additional graphics cards in future, which you will probably need if you want to play with VR. I ended up overdoing the power supply. I plugged my configuration into a Kill-a-watt meter to see how much power it is using. It draws around 40 watts with no applications running, and goes up to around 90 watts when I am doing an encode with Handbrake. The other thing I found with the power supply was that it provided 8 SATA power connectors and 8 Molex. Everything in the box is SATA, so I would like a power supply with 12 SATA so I don't need to use power splitters or molex converters.
Another interesting thing with this board was support for M.2 SSD. It seemed like a feature I wanted, but I discovered that using an M.2 SATA SSD disables SATA ports 0 & 1. Using a PCI M.2 SSD leaves ports 0 and 1 available, but PCI is much more expensive. I ended up going with a Samsung Evo SSD connected to one SATA port to hold my OS.
I have the machine connected to a small TV with HDMI, but most of the time I connect with VNC from my laptop. I use DLNA to play on my main TV, and also can either cast to Chromecast, or use my Roku to play recordings. Playback in HD is smooth with no glitches over the local network.
I don't have any experience with Bluetooth but it should be easy to add. My board has 8 USB ports combined USB 2 & 3.
I guess this is not really a recommendation as to which way to go, but hopefully these few points might help guide you to your preferred solution. Good luck.