Me personally (and all I've been setting up lately are servers) I use this as a start:
http://www.bsdguides.org/guides/free...ity/harden.php
And go on from there depending on each service that needs to be run. I've also been building ezjails (I like it for its low overhead and read only base system) lately. One for each service I want to run (For example, one is running Apache/OpenSSL/PHP, another is running MySQL, another running PostgreSQL, and yet another running VSFTPd). I find it tends to make each jail easy to secure as there is relatively little installed in each jail.