Mail Server setup

I would suggest to use LINUX and use Qmail. Chekcout cool tutorial on Qmail on
www.qmailrocks.org

Personally, I'm a CLI (Command Line) type of guy, but when it comes to mail servers, my experience has taught me you want some things done quickly so you can save time and 'skip' the learning curve - which also requires time.

Popular email servers such as qmail, exim mail and sendmail, seem to be more robust once setup correctly (I won't bet my life on the last one:> ) but require an awful lot of time to do so. Plus, the fact they don't usually include an integrated webmail browser is also another negative point for me.

Of course, there are other products which will provide everything the cli-based mail servers don't, plus a lot more, but they seem to be somewhat more 'sensitive' in terms of reliability - or at least I personally haven't had the best of luck with them.
I've worked with Exchange 2000 & 2003, Merak Mail server, Mail enable, Exim and sendmail and still haven't found that 'awesome' mail server I can recommend to fellow engineers! All of them have their positive and negative points.

I also checked out smitherton's suggestion (Zimbra) which looked promising, until I got to the license part

I'd really like to hear what other people have to say about full mail server solutions (web mail, groupware support, antivirus, antispam, pop & imap support and all the rest).

Cheers,