I have had two WordPress blogs hacked into in the past. That was at a time when I was doing very little internet marketing, and until I found time to address the situation (months later), these sites were penalised in the search engines. They were not removed, but the rankings were reduced.
In my opinion, the best way to make sure that your is via using a clean hacked wordpress site backup plugin. This is a fairly inexpensive, elegant and easy to use way to be sure that your website is available to you in case of a disaster.
The one I recommend, and the approach, is to use one of the password creation and storage plugins available for your browser. I believe after a trial period, you need to pay for it, although Lots of people like RoboForm. I use the free version of Lastpass, and I recommend it for those who use Firefox or Internet Explorer. That will generate secure passwords for you.
Before you can delete the default admin account, you first need to create a new user with administrator rights. To do this go to your WordPress Dashboard and click on User -> Create New User. Then enter all the information you will need to enter.
Now we're getting into matters. Whenever you install WordPress, you need to edit the file config-sample.php and rename it to config.php. You want to install the database information there.
Implementing all of the above will probably take less than an hour to complete, while making your WordPress site considerably more immune to intrusions. Over 1 million WordPress see post sites were cracked last year, largely due to easily preventable safety gaps. Have yourself prepared and you're likely to be on the safe side.