I like to leave Thunderbird open because it checks for e-mail every 5 minutes or so but I hate having it in the taskbar in the bottom... is there a way to minimize it to the systems tray?

There is an extension available to do this. More info HERE.

EDIT: I was just reading some of the user's comments on the download page, and for some it does not work, and one complained that it would not uninstall. Just a head's up!

Also I believe somewhere in the settings of the Thunderbird you can check the option to minimize it to the system tray instead of the taskbar. Just look through the settings and you might find it.

Hmmm... The last one seems interesting but it is missing a Binary Component. That is what the error message said.