I love that you can modify Firefox to serve your unique needs by adding search engines, themes, and extensions.

Extensions

1-Click YouTube Video Downloader – I like to save & play my favorite videos on my computer.

1 Password – Some of you only use one or two passwords, not me. I use 1Password to keep track of them on Macs. I primarily use free programs, but like 1 Password so much it’s one of the few programs I am willing to spend money on. Use a Windows computer? See RoboForm.  Technically 1 Password and Roboform are both toolbars but I think of them as extensions of my browser’s productivity.  So there!