For a frugal (to have the passworded stuff), you can boot with 'dsl secure'. This will also encrypt your backup.tar.gz afaik.
In my case that isnt accebtable method. I have DSL that runs on server computer. Mainly remotely contolled, via ssh or vnc.As bkil said, the main file involved here is /etc/inittab. The multiuser version spawns virtual terminals on which you can log in manually, and the default one starts a bash login shell from the current shell.