Hey Patrick...
Try looking at these:
i.Scribe (or InScribe for more features):
http://www.memecode.com/index.php
TheBat!
http://www.ritlabs.com - important: IMAP4 (I use this client, but with POP3 accounts)
ABout.com lists a load of email clients... One weekend I went through nearly all of them. Including Eudora. Man, what a piece of garbage. So many versions latr and they've continued to build on such a weak foundation. Qualcomm is an IP company lacking any merit whatsoever in my opinion. It was a sad state of affairs for email clients. I didn't like Mulberry. POcomail looked very promising but I had HUGE issues with its skins. Taste issues. And some configuring options were a PITA.
I had already been using TheBat, but there were just a couple of small little things bugging me (its editor is currently free-carat - pretty powerful, but I wanted a fixes carat editor). The new betas offer a new optional editor and more features are coming. It doesn't have an equal as far as I'm concerned.
Scribe I know of because I was using a little paint program from the same author called iMage. Ever try finding a good (any?) bitmap (1-8bit CLUT bitmaps) editing program for wndows? I do mean something that isn't a complete pile of rubbish like MS Paint. I found only iMage and Promotion which are the only programs that come anywhere close to DPaint and Brilliance on the Amiga.
Bruno