vim, emacs, postgres, zsh, bash, urxvt, systemd, pacman<p>EDIT: It all depends on how you set the bar, though. There are plenty of projects whose entire documentation is a README with a few examples.<p>Also, what's "best", documentation that greatly explains a horrible, unintuitive interface of a program or one that hardly needs to exist because the use of the program is so intuitive, you don't need documentation? Greater effort was spent in the former, but you understand the program better in the latter.