server services w/mutiple ips

I have a question with multiple ips and services running on the server.
bind, postfix, and courier should listen on only 1 ip correct? and is it ok to have them listen also to localhost?
mysql, apache, proftpd can listen on all avaliable ips correct?

 

on my debian etch server, bind, postfix, courier, and proftpd are listening to all IPs per default.
apache2 also, but I don't remember if there was a configuration to do for this.
I don't know for mysql, I only listen localhost for this one

 

I'd let all services listen on all IP addresses (incl. localhost).

 

Thanks guys, just doing some homework before I started adding ips.