You may want to add one more 'server' to your ntp.conf file: localhost.
Adding the following two lines will add the system clock to ntpd(8)'s list of time servers. This way, if the network goes down you'll still get some kind of synchronization:
fudge 127.127.1.1 stratum 10
Also, it's generally not a good idea to use ntpdate; the sudden "popping" of time can cause havoc with certain programs tha rely on file date/time consistancy: make(1) is one very good example. It's best to run the ntpd(8) on the "clients" as well so the popping of time.
P.S. Can yoy guys add a "Preview" button so we can review our posts before they're submitted?