Free GUI E-mail Clients For X11?

TheLocustNMI asks: "My question is this: Are there any stable, easy to use GUI e-mail clients out there? I'm in the process of making the switch from Win9x to Linux, and I'm finding it hard to get hold of a decent GUI mail program. Most of the ones I do find are PINE or MUTT, etc. But, coming from Win9x, and as much as it pains me to say so, I liked Outlook. It was easy to use and configure, and wasn't too terribly huge. I've looked into Balsa and Adora, and I've used KMail, but they are either not stable enough (Balsa), not in development anymore (Adora), or just plain clunky (KMail). I would have expected more GUI clients out there, but so far, I've come up with a very short list. Ideas?" Lately, I've been using Pronto, a GTKPerl based email client that supports multiple accounts, filters, MBOX, Maildir and POP3 support. Pronto was originally CSCMail but CSCMail has since moved to C.