My standard set of AddOns. Also includes HTTPS Everywhere (https://www.eff.org/https-everywhere).
Blocks annoying video ads on YouTube, Facebook ads, banners and much more.
Adblock Plus blocks all annoying ads, and supports websites by not blocking unobtrusive ads by default (configurable).
The first and only download manager/accelerator built inside Firefox!
A customizable mouse gestures extension which enables to execute various commands and user scripts with six types of gestures.