"Vim users stick with Vim in no small part because muscle memory
is so powerful--once you've learned Vim's keybindings, it's
possible to be extremely productive in Vim without ever taking your
hands off the keyboard. If you'd like to imbue Firefox with Vim
power, embrace the Vimperator extension. Vimperator turns Firefox
into a no-nonsense, modal Web browser.
"The Vimperator 0.4.1 extension is available on Mozdev.org. To
install the extension you can download it to your hard drive or
just click on the most recent version. You may need to add the site
to your allowed list of sites for installing extensions. Firefox
will display a bar at the top of the page if the site isn't on the
allowed list -- just follow the prompts..."