Sylpheed for Windows

Sylpheed is an email client and news reader based on GTK+ GUI toolkit. It's full of features designed to help you get more from your messages and improve the speed at which you receive and process news feeds. Although it's designed for Unix systems, it also works on Windows although the GUI is not exactly what you might expect from an e-mail client. It's very no thrills with few graphical attractions but as you would expect from a program designed for Unix platforms, it's very secure and functional. The program is also remarkably well-organized, lightweight and supports just about every e-mail protocol you'll ever need. It's also designed for those that need maximum security because it supports not only the standard SSL protocol but also GnuPG and TLSv1.

In addition, it comes with more standard functions you would expect such as a powerful filtering and search tool, junk mail control and external commander that allows you to do away with the mouse for a while. It doesn't seem to allow you to retrieve mail from other POP3 accounts though although there is an extensive forum that no doubt, allows you to do this.

A very secure and highly professional e-mail client that doesn't make it easy for beginners but will certainly please those that need high security and work across platforms.