This week I finally got Eudora, a 32-bit Windows application, running on my 64-bit Linux system using the Debian WINE package. So far it has proved to be very stable with only a few temporary graphic glitches. I've not used Eudora for years now and though it has long been my favourite email client I'd have to say I think it's lack of threading and VERY poor IMAP perforce now means I'll have to promote KMail to number one email client.
On the upside, the Eudora team have released a Eudora extension to Thunderbird and an alpha build of custom Thunderbird/Eudora hybrid, so there is hope that they may improve Thunderbird to a usable state.