Keep the following types of users in mind when designing your website:

The Virgin
For lack of a better term, this is a first time visitor.  They have to learn your site from scratch.

The Novice
This user has been to several similar sites but never to yours, there is still a learning curve.

The Repeat
This user has been to your site and knows their way around, but can still get lost.

The Techie / Designer
This user has the highest intimacy with technology and therefore the highest expectations and is generally not very forgiving.

The Intimate
These are the people that are too intimate with the site and create unrealistic user expectations.