I personally like rcNG from FreeBSD (it possibly was borrowed from NetBSD, but I don't know the details).

It is a great compromise between a shell script and a configuration file.

Here is example of a simple use:

http://svnweb.freebsd.org/base/releng/10.1/etc/rc.d/bsnmpd?r...

But when you need more control, you still got it:

http://svnweb.freebsd.org/base/releng/10.1/etc/rc.d/motd?rev...