Mutt is lightweight yet very powerful text-based mail client for UNIX machines. It seems to be a combination of ELM and Mush mail clients.
K. Scott was the SysAdmin for the Tech Computer Center and was a mush and UCBmail user for ten years. Finally, during the spring of 1999, we began moving our suns to Solaris-7 from SunOS-4.1.4. I began porting some of my legacy software (like tvtwm and mush). Someone pointed out a new mail client that; supported imap/pop/pgp/mime, was very configurable, could do colors and HTML, and most importantly it was not Pine. So, since it had been about 5 years since I changed mail programs I figured it was about time.
Mutt seemed to compile pretty well right out of the box. My two most used platforms are ix86-Linux-2.0.33-Slackware-3.6 and SPARC-Solaris-7. Our mailserver is a linux box providing mail via POP3/IMAP/NFS.
In my muttrc you will find my likes, dislikes, and tricks to get mutt to do what I need. It is pretty well commented.