Do I need DNS service running?

Sorry I'm new to OS X Server and am still learning the proper setup process. I have a small home network and am using leopard server primarily because I want to take advantage of the External Accounts feature. I'm installing 10.5 Server on a mac-mini which is behind my router (An Airport basestation). The basestation is set to distribute IP addresses and I've always been able to see other machines that are on the .local namespace. With this inn mind, should I still activate the DNS service on my server?