Firefox: If you're trying to cut down on the amount of mousing around you do, MouseControl is a simple Firefox extension that enables speedy tab switching via your mouse scroll wheel — no more dragging the cursor around.
Install MoueControl, restart Firefox, and from then on you can scroll through your tabs via the scroll wheel. Right click and hold then scroll to move from left to right via the wheel. Left clicking during the scrolling process will kick you back to the initial tab — you can use the scroll+left click as kind of a quick-peek tool to glance back at another tab before quickly returning to the original.
Watch the simple demo video above or visit the link below to grab a copy for yourself. MouseControl is a free extension and works wherever Firefox does.