Rated 5 out of 5 stars
The new icon should have transparent background. Looks weird on FF4.This review is for a previous version of the add-on (1.3.0). This user has other reviews of this add-on.
Done in v1.3.2 - https://addons.mozilla.org/en-US/firefox/addon/adban/versions/?page=1#version-1.3.2 (this version is awaiting for review). Unfortunately I have no graphical designer skills in order to create more appealing icon.