I like how customizable this is, being able to change the icons, time to check email, commands to run when you click the icon, get mail, or have no mail. For how customizable it is, its also very simple
Only one drawback is it only notifies you of new email in the inbox. If you have filters that auto organize your mail, you miss alerts on those messages.
This does require a few dependencies on Ubuntu 10.04, command below.
It may require more, but these were the ones it bugged me about. after I installed those, everything worked fine!
Would love to see a version that checks all folders
Run this command to get it working on 10.04, most likely works on other versions of Ubuntu
sudo apt-get install libgtk2-trayicon-perl libxml-simple-perl libcrypt-ssleay-perl