According to Sitemeter 50% of visitors to my blog are using Firefox. Who am I fooling - I probably account for half the Firefox visits myself! Nevertheless I take pleasure in sharing with you my current favourite firefox extension: Split Browser.
It allows you to display your Firefox tabs in tiled mode at the click of a mouse. Here is an example:
If you are familiar with Lotro you will notice that I have three of the most popular Lotro help sites open side by side in tiles all giving me info about a quest. Not that I resort to such cheating myself of course ;)