As runs the fox so flies the bird

Ahhh, Exchange: the bane of the corporate Mac user. If iCal had Exchange integration I would completely free of the shackles. I can tie Mail.app into our Exchange server, but still have to keep a Remote Desktop session open to my PC for the calendaring.

Yes, I have Entourage. I refuse to use it any more. It's a bloated resource hog and has proven to be the only app I have that regularly crashes. So, Outlook it is at least for calendaring.

Thanks everyone for your input, and thanks Adrian for the headline compliment.

Since Palm sync for OS X is a tricky business to begin with, it seems like Thunderbird synchronization to PIMs would be a good opportunity
for mark/space (Missing Sync) to develop a conduit.

http://www.markspace.com/missingsync_palmos_conduits.html

Nice headline, Michael!

I used Thunderbird on Windows for all my e-mail before I converted to an all Mac household. I've waffled back and forth between Thunderbird and Apple Mail a few times, but keep going back to Apple Mail. Not because I like it better, but because TB doesn't interface with the Apple address book. I use a Palm and Missing Sync to synchronize with address book and iCal. I don't want to have to maintain all of my contacts in a separate address book and try to keep everything up to date. An additional (albeit, minor) annoyance is lack of support for apple script, which means e-mailing pictures from iPhoto isn't as butt simple as it is when using Apple Mail.

The thing that keeps it on my machine is the desire to use nntp newsgroups. I've tried other clients for that, but none of them have made me happy so far. Why isn't there a version of Agent for the Mac?

I'd love working with Thunderbird. Plaxo somewhat relieves the discomfort of the separate address book, so it is workable.
The main thing I'm missing however, is 'combining' inboxes (and other mailboxes, too) from several accounts like Mail.app does. I want to see all my unread messages in one smart folder, but it doesn't let me.

I am in the somewhat unfortunate position of being the person who led the charge to make Thunderbird the standard email client at the college where I work. One of it's big advantages for us is that it's preferences are nearly identical between the Windows and OS X versions. It's a more-than-decent email client (though I use Mail.app, myself) that has a lot of funtionality.
I said unfortunately at the beginning because T-bird's big downside is the lack of a reliable Palm conduit. The college's cabinet and other bigwigs use Treo 650s and we have major, major pains consistently getting the T-bird address book to sync (this is on WIndows computers.) And I am the go-to guy for the fixes.
My advice to people who want to use Thunderbird is:
On Windows, without the need for Palm connectivity, go for it. It's the best, free client out there. If you need Palm support, look elsewhere.
On Mac, use Mail.app.

I wrote about my struggles with Thunderbird a while ago:

http://blog.innerewut.de/articles/2005/05/07/struggle-with-mail

Not mutch has changed since then.

hi, this is my first comment here.
you've my own point of view, and so id like to share my opinion with you.

- under windows, there's no better email client than thunderbird.
- under osx, as for the fox compared to safari, with thunderbird you can access
to a set of plugins, themes, features that mail doesn't have, but
Mail.app is really "integrated" into the os.

In my opinion a "sweet switch" can be obtained using T-bird for a while,
with an IMAP account, for example, testing the various features.

When i speak about "integration" i mean two aspects: the address book and spotlight indexing... maybe with the 2.0 version it can be done... maybe...

bye bye
(sorry for my poor eng, im italian! =)
michele