95% of "here's how to fix that braindead default that's giving you troule" or "here's what that misleading error message means and how to fix it" how-tos or whatever, for servers, are written either for Ubuntu or Red Hat (and friends) and sometimes the exact same steps won't work even on Debian. 3rd party commercial software often supports only Ubuntu or Red Hat, and you're on your own if you use it on something else. I've never liked RPM-based distros and specifically dislike Red Hat as a company, so, Ubuntu it is.
(For work, where I just want something that won't make me "the asshole who chose [non-standard thing]". I prefer Void or FreeBSD or, sometimes, Debian, for my own stuff)
[EDIT] Oh, right, specifically for desktop? Yeah, I'd go Void or Arch probably. Buuuuuut if it were for work, I'd just use Ubuntu, even on the desktop, so it wouldn't be my fault when it misbehaves.