Microsoft may–or may not, depending on who you listen to–stop
development on Outlook Express. If they do, then the Windows world
needs a new email client. Even if they don't stop development, people
would be better off using a nice email client with fewer security
risks. Mozilla Firebird
is well suited for this task. Firebird is a good looking, feature-rich
email client which doesn't even require using an installer. Binaries
are available for Windows as well as almost any other platform you
could want to run (OK, maybe you can't get if for your VAX).
Spread the word. Promote Firebird!