FWIW, I really like Cyrus as an IMAP server. Hopefully the docs you read have a good HOWTO on how to set up the authentication, though, as it can be a real pain in the ass.

I like Postfix, too. It's pretty tidy yet has all the options you really need for a MTA. My only other experiences are with Sendmail and qmail, though. I like postfix best of those.

I've got no real suggestions as far as clients, but I'd caution against using fetchmail, solely because if you just download all your mail, you get rid of the advantages of IMAP.