This might not be the place to pose this question, but I think most of the people reading this post have gone through this decision making process as well. I have installed Zimbra and like it's functionality but ultimately it's more than what I need. The web interface looks great but with all of the functionality I think can overload my server and clients.
What I'm looking for is a simple SMTP/POP/IMAP server that can do SSL over all protocols and can support multiple domains. Having a web interface is critical but I would prefer something that is much simpler than the Zimbra GUI. Something that will run much smoother on modest hardware (server = 512MB RAM, 2 Ghz Processor). I've come across commercial alternatives such as Merak which seem to offer everything I need, but they do not offer a free version that has the functionality I'm looking for. Since this is a real small implementation I'm not looking to spend any extra money.
I would prefer a Linux based system, but would consider Windows. Even if there is no one solution out there and I wind up having to piece together something using different applications like Postfix, Sendmail, Cyrus, etc, that's OK, I've had to do that before. Web clients such as SquirrelMail are a little too simple, however.
Thanks for your help,