I've been a long-time hater of Eudora, so I've stayed clear of it. I've always thought it was one of the worst email clients around (not including the ones that lack so many features that they're not even worthy of consideration). Have always been extremely disappointed with the Mac and Windows versions I've seen.

Thunderbird seems to represent what I've always thought a mail program should be. At least it's the closest. I've been using TheBat for a few years now, and although it's certainly powerful, it's a right pain in the ass for some things and has a bunch of bugs in the final version I have - beta versions of the newer release introduce other bugs that I'm not willing to put up with.

The fact Thunderbird is available for Windows and Mac OS X seals it.

Bruno