touching on the admin account... like zencoder mentioned, do NOT delete the admin account... what you can do however is rename it. on all my systems, i open up the properties on the admin account, and 'cut' out the description. i then set a complex password (8-16 characters combine alpha-numerics and special characters). then i rename the entire account.

after that, create an account called 'administrator', pasting in the original description, and DISABLE this account. a quick and easy way to make your box just a bit more secure.