thunderbird [-P profile]
Thunderbird provides IMAP/POP support, a built-in RSS reader, support for HTML mail, powerful quick search, saved search folders, advanced message filtering, junk mail controls, message grouping, labels, return receipts, smart address book LDAP address completion, import tools, and the ability to manage multiple identities in email and newsgroup accounts. Thunderbird provides enterprise and government grade security such as S/MIME, digital signing, message encryption, and support for certificates and security devices.
If no profile is given to the -P option, the profile manager will pop-up. You will be allowed to create or select a profile. Thunderbird then launches with the selected profile.
The Thunderbird Homepage: http://www.mozilla.org/projects/thunderbird/
The Debian Thunderbird FAQ: http://www.jwsdot.com/debian/faq.html