The de facto standard for Raspberry Pi operating systems is Raspbian–a Debian based distribution specifically for the diminutive computer. Of course, you have multiple choices and there might not be one best choice for every situation. It did catch our eye, however, that the RaspEX project released a workable Ubunutu 16.10 release for the Raspberry Pi 2 and 3.
RaspEX is a full Linux Desktop system with LXDE (a lightweight desktop environment) and many other useful programs. Firefox, Samba, and VNC4Server are present. You can use the Ubuntu repositories to install anything else you want. The system uses kernel 4.4.21. You can see a review of a much older version of RaspEX in the video below.
If you are used to using Ubuntu, this could be a great convenience. The project claims the system is much faster than the stock OS, although it doesn’t offer any explanation for why that should be so.