I'm not going to be a complete spoiler for you, but I will tell you what add on is number one. I'm sure you can figure it out. Well if you guessed right, it is AdBlock Plus. AdBlock Plus has been downloaded over 166 million times, and has over 13 million daily users. Firefox fans love this addon because it gives them control of what they see on the web, and it can also block other items from web pages besides ads. So If you don't what those annoying widgets on some sites, you can right click on them and block them accordingly.
While I don't use Firefox as much as I use Chrome, I do have my own fair share of add-ons installed. From Adblock to Firebug. I even have a few custom themes installed, but currently I have reverted back to the default theme.
