Among other new features, Thunderbird 2.0 adds message tagging, saved searches, more descriptive alerts that include email snippets.
Even if you like Gmail's web interface, a mail client is still useful to backup your email and for reading your messages offline. If you use multiple email clients, your Gmail messages are available only to the first client that requests them. To change that, replace name@gmail.com with recent:name@gmail.com in your client's settings.
