Gesturefy is a good addon, but it should be run in High Priority to enable it to draw over webpages smoothly and accurately. Often times I try to perform an action, and it lags or doesn't register the entire mouse gesture, and I have to repeat it.
This really makes me miss the good old built-in mouse gestures that the old Maxthon browser had a few years back. To this day I haven't seen any other browser that has as smooth and reliable gestures as the old Maxthon browser did (v1.6.x).