I have been using Mozilla's Thunderbird as my default email application for only a few months now.  So, I figured I would share some basic how-to articles so you can quickly get Thunderbird up and running the way you want it if you choose to switch.  Adding a signature to your outgoing emails is always important. 

First open Notepad and create your desired signature. 

Your IT & Music Guide Through The Cyber Galaxy

http://blogs.howtogeek.com/mysticgeek

Save this text file in a familiar location on the hard drive.  I put mine in Documents.  Next open Thunderbird and click on Tools \ Account Settings.

Keeping the default dialog box open, in Default Identity check Attach this signature:  Then browse to the location where you kept the signature text file and click OK.

Now the signature will show up any time you create a new email message.

There are also several cool Add-ons for Thunderbird for further manipulating your email signature.