I have presently set up my new server to use Postfix and virtual mailboxes. I want to add Dovecot to that and then do something reasonable on top of it, like SpamAssassin.
I highly recommend that anyone who wants a very lightweight, *very* effective, brain-dead simple (installation *and* maintenance) anti-spam gateway check out ASSP (http://assp.sourceforge.net/)... it was already one of the most effective options available, but there has been a *lot* of activity recently, and the improvements are amazing. Combined with ClamSMTP (http://memberwebs.com/nielsen/software/clamsmtp/) - also very light-weight, very easy to install, configure and maintain - it has reduced the load on my server drastically (through its early HELO checks, and the new PB (PenaltyBox) functionality, and is virtually maintenance free.
It replaces (for me) SpamAssassin, Postgrey and RBL - and I could most likely do away with ClamSMTP as well (haven't had a virus get past ASSP yet, in about 4 months, since I installed ASSP).
1.2 is in the late beta/RC stages, and will most likely be released in the next week or two. The only negative is, it has been changing so rapidly, that the documentatiuon hasn't had a cnahce to catch up.
These recent changes began as unofficial changes by Fritz Borgstedt, who was later made an official developer. You can read all about these changes in the mail list archives.
As for the other parts, I use Postfix, and am in the process of converting from Courier to Dovecot (which is why I'm here)...
--
Best regards,
Charles