Mouseless Firefox

Firefox's default keyboard shortcuts do a pretty darn good job of giving you everything you need to browse the web mouseless.

Backspace = Back
Shift + Backspace = Forward
Tab = Next Field (If you didn't know this one already...)
/ = Search Text
' = Search Links Only
F3 = Search Again

Once you've got a link selected:
  Enter = Open Link in current tab
  Ctrl/Cmd+Enter = Open Link in new tab
  Shift + Enter = Open link in new window

Spacebar = Page Down
Shift + Spacebar = Page Up
CMD + L = Jump To Location Bar (CTRL + L on Windows, I think)
Ctrl/Cmd+Tab = Switch tabs
Ctrl/Cmd+[1-9] = Select tab (1-9)

You can find the full list of firefox shortcuts here