Windows for my HTPC, Ubuntu for my work and personal laptops. Windows is on both of the laptops though I don't have much of a reason to boot into them.

It's a hard thing to recommend to most people unless you really have the motivation to stick with it and figure out the nuances. It's hard for me to go back to Windows for anything other than games, though. As a developer there's just no analogues for Windows that come close to matching the workflows that Linux gives you. (And I have no desire to pay Apple tax ever)