Using Vim in my project has really helped my skills in that editor. That's what working with a couple dozen small Vim files per day will do for you.
I had to ssh into a server yesterday and set up a small script and a cron job, and I could feel how different that process was now that I can do more with Vim.
I can move around in files much more easily, and I know the basics of copy/move/paste, which is more than I could say before.
Clojure is trying to push me in the Emacs direction, and maybe I could get comfortable with that editor, but the universality of Vim/Vi is hard to ignore.