I have been planning some preliminary stuff for the new server. For one thing I've decided on using Gentoo on it, and have therefore read up on some documentation. I will most probably use qmail together with vpopmail and a MySQL back-end and serve POP3 and IMAP over an SSL enabled connection.
I will as before also use Apache2 together with PHP5 and MySQL 5.0. The webmail frontend will probably be squirrelmail configured with the OpenPGP extension (Read more about OpenPGP).
More information on the process will follow.