The new Thunderbird email client is out. Version 0.6 is available HERE.
The new look (matching firefox) is in this release and I found this interesting mini-history on the development of the new icons for Thunderbird HERE.
Note that Thunderbird .6 no longer supports LDAP v2 for address book. I had to upgrade my LDAP server last night, I’m now running OpenLDAP 2.2.11 which supports LDAP v3 instead of 1.2 which did not 😉
I really like the the addition of the visual “new mail notification” on the dock icon in OS X