Actually, I always delete the account that I am forced to create during Windows setup.. and I actually name this account "Delete".
As soon as Windows boots up for the first time, the first thing I do is enable the builtin admin account and delete the account named "Delete".
The first account you make in Windows 7 is already a member of the Administrators group though.
just finished moving everything and deleted my account that i created on install and rebooted. it is gone and now am running with the default administrator account