Whats in a system name?

Hi, I was wondering what is the proper way to name a suse (linux) machine. In Yast there is DNS and Host Names. There is another option for Host Names. In a machine that is a server for my internet domain name (me.com), should I use that as the Host Name (in DNS and Host Names), or should I name the machine any name, and enter internet domain name in Host Names? I'm not doing any DNS stuff locally, I use my ISP's DNS servers, and have a dynamic IP address from them (with RunDNS running of course). My Suse boxes are not routing at all, I have a little home box router doing that. Hope this dosen't sound like a "Who's on first" excercize. TIA, Jim