Set mousewheel.horizscroll.withnokey.action=0 and mousewheel.horizscroll.withnokey.numlines=1 to avoid Firefox jumping around the history when scrolling horizontally.
Thinkpads and IBM keyboards, it has a couple little keys above the arrow keys that go "back" and "forward" in your browser. At least, in Windows IE. Shockingly, they don't work with Firefox (in Linux) out of the box.