I think it really depends on what you intend to do with it... Many answers here will mention what they use but not why.

In my case I want to have various services installed in docker containers, and I have the skills to manage Linux in console. A very simple solution for me was to use a rock-solid, established Linux distro on the host (Debian stable) with Docker sourced from its official apt repo. It's clean, it's simple, it's reliable, it's easy to reinstall if it explodes.

Why containers (as opposed to directly on the host)? I've done both over several years and I've come to consider the container approach cleaner. (I mention this because I've seen people wondering why even bother with containers.) It's a nice sweet spot in-between dumping everything on the host and a fully reproducible environment like nixOS or Ansible. I get the ability to reproduce a service perfectly thanks to docker compose; I get to separate persistent data very cleanly thanks to container:host mapping of dirs and files; I get to do flexible networking solutions because containers can be seen as individual "machines" and I can juggle their interfaces and ports around freely; I get some extra security from the container isolation; it's less complicated than using VMs etc.