Have you tried Postbox? (http://postbox-inc.com/ http://postbox-inc.com/) It's a commercially maintained fork of Thunderbird that runs on Mac & Windows, and it

Have you tried Postbox? (http://postbox-inc.com/ http://postbox-inc.com/) It's a commercially maintained fork of Thunderbird that runs on Mac & Windows, and it's the only email client that keeps my email life sane. (Though I've had to install a plugin to add back email-priority functionality.)