Just to document my mail setup. I use Mutt, offlineimap, mairix, msmtp and newmail. It's a bit of a faff getting each piece setup, but doing so lets you understand how e-mail actually works - a first step towards reaching command-line Enlightenment, turning your window manager off and entering the monastic freedom of the shell.
The Arch Linux wiki has a really good guide on how one sets up Mutt using either OfflineIMAP or getmail/procmail (for POP3), msmtp (for SMTP), and links to the right stuff to read about using Mutt, Vim and links. Just remember 'pacman' is Arch's package manager - aptitude/apt-get/fink/port (or download RPMs or tarballs or self-extracting EXE files) as appropriate.
If you've got a fast net connection and are not worried about offline access to your mail (and, well, you should - networks go down, and even 3G-toting cloud bunnies have to use trains and planes occasionally) can use mutt to access their IMAP servers directly. See this or this blog post for details.