Did you know that you can cycle through your open tabs without clicking on them?
All you have to do (in Windows) is press CTRL+Page Up to cycle left or CTRL+ Page Down to cycle right.

When typing in a domain name in the URL address bar, Firefox can finish the top 3 extensions (.com, .net, .org) for you! Just type in the domain name without http://www. or the extension (i.e. evolvemedia) and then do one of the following.

Pressing Shift+Enter will finish a .com domain name.
Pressing CTRL+Enter will finish a .net domain name.
Pressing CTRL+Shift+Enter will finish a .org domain name.

If I find more, I’ll add them to the list!