I generate unique passwords using command-line tools like apg and pwgen and store them in an encrypted Emacs org-mode file [1]. Emacs can open files transparently via SSH [2], so I have easy remote access to my password store without having to rely on any external service.

[1] http://orgmode.org/worg/org-tutorials/encrypting-files.html

[2] https://www.emacswiki.org/emacs/TrampMode