OS X Default User Template
First, it's important to note that I've run into problems using the instructions from Mike Bombich's site here. The last few times I followed these instructions the default user template didn't stick. In fact, I've actually had more luck with the instructions posted by Glenn Rees in this forum post.
1. Tweak your default account including setting dock, clearing cache, recent items, etc. I usually name this account "teacher."
2. Login to the machine as root (I've had problems when I did these steps under a straight admin account as sudo).
3. Create a backup of your current English.lproj template. Don't just issue a mv (move) command to rename it-- create a copy of it using ditto instead.
3. Delete the default home directory files under English.lproj in /System/Library/User\ Template/English.lproj. Don't just delete the entire English.lproj directory!
4. Issue the following commands:
:~root# cd /System/Library/User\ Template/
:~root# sudo ditto -rsrcFork English.lproj/* English.lproj.bak
:~root# sudo rm -rf /System/Library/User\ Template/English.lproj/*
:~root# sudo cp -R /Users/teacher/* /System/Library/User\ Template/English.lproj/
:~root# sudo chown -R root English.lproj
:~root# sudo chgrp -R wheel English.lproj
5. Restart, log in as admin and repair permissions before creating a new account to see if it worked.
I know the sudo commands above are redundant but I just do it as a matter of habit. Slashes and astericks shown in commands above are critical! Also, I've read in some places that permissions on the default user template aren't important but I chown and chgrp on it just to be safe.