Thunderbird the email client from mozilla (the same people that bring us Firefox) is my email program of choice.

It does IMAP well (better than Outlook Express which downloads your messages instead of leaving them on the server where they belong) and has a nice interface.

My only problem with it is that sometimes crashes in my Windows virtual desktop when something sends it a resize command it can’t handle (I assume this is the case because when I restart it, it starts in the “default” size/position (minimum size in the upper lefthand corner).