Esoteric network setup question

[inbox]

I have a hopefully not silly question;

When I'm setting up my network, does it matter if I give the domain a TLD 
or not?  Say I call my home network "myzoo".  I don't ever plan on 
registering "myzoo.org" as a domain, and I don't ever plan on connecting to 
my home network from the outside (TOS of my ISP forbids servers 
anyways).  Should I call it "myzoo.org" or just "myzoo" in the network 
configuration dialog or does it matter?  Do any programs expect a TLD for 
the local domain?  The only reason I ask is every example in every book 
I've seen has a TLD in the domain name, usually .com.

Christopher