Fair enough if you wanna run Linux as root all the time, but there's really no reason to delete the main user account.
The biggest danger would be to run your web browser as root, but fair enough, I've no interest in trying to convince someone of not being root all the time.
On my own computer I have a separate user account simply called "visitor", and I log into it if someone wants to use my computer to surf the web or whatever, and it hasn't got sudo priviledges. It's also good for keeping my Firefox favourites private and also my Auto-complete phrases (and I've got some pretty nasty auto-complete phrases). Plus they can't access my own data.