I use Claws Mail, and have been using it for 10 years. It is fast and can handle a lot of email. It has many options and integraes nicely into the XFCE desktop.

I use Claws Mail, and have been using it for 10 years. It is fast and can handle a lot of email. It has many options and integraes nicely into the XFCE desktop. It is a fork of Sylpheed, and I assume the two have diverted quite a bit.