A VPS is great for hosting a corporate or private E-mail server. Since you get root access to your system, you can choose the E-mail MTA (Postfix, Qmail, Sendmail, Courier, et. al. ) and client services (POP3, IMAP, SSL) you wish. You also have the ability to configure them exactly the way you want, whether you're authenticating from a SQL database, using special SPAM/Virus scanning, etc. Bets of all, there are no limits on the number of E-mail accounts or forwards available. You can even launch web-based Email, like Squirrelmail, Roundcube, Horde, et. al.