Thunderbird blows. After much goading from ScottC and others, I downloaded it and gave it a try. More or less the same functionality, but that editor sucks, sucks, sucks. Ugly, clunky UI, nonexistant multi-language support. no inline spell or grammar checking, etc. It *did* import all of my Outlook messages, but lost all of the search folders, making it basically useless.

A day later I was back to Outlook. It isn't perfect but for me it is a hell of a lot better.