There are a few settings that I change in Mozilla Thunderbird when first configuring the e-mail client. They are below, as follows:

1. Uncheck [ ] \"Show only display name for people in my address book\"
Click Path: Tools > Options > Advanced > General (Tab)

2. \"Text Format: Send the message both in plain text and HTML\"
Click Path: Tools > Options > Composition (Tab) > Send Options > Text Format

These settings make Mozilla Thunderbird a far more enjoyable e-mail client to use. Enjoy!