When I used Vimperator (I finally changed back just because I don't like how FF performs on OS X) I found I was strongly bimodal — surprise — where I'd spend the majority of my time just using the keyboard, both hands, and then if something demanded the mouse I shift to my trackpad.

The thing I want to point out is how loathe I became to switch to that trackpad. Vimperator makes you despise flash even more.