Drupal Hide "Create Content" Page
I put this in a comment already, but here are some more detailed instructions on how to set up permissions to restrict access to content types.  I assume you are using Drupal 7; if you're still on Drupal 6, the exact sequence of clicks will be different, but the basic approach is the same.


Log in as an administrator.
Click People in the nav bar at the top.
Click the Permissions tab (top right of the People overlay).
Click the Roles sub-tab (immediately below Permissions tab).
Add a new role using the text box at the bottom of the overlay.  For example, "editor".
Click the "Permissions" sub-tab immediately to the left of Roles.
Go down the list of permissions and choose which role can do it.  For example, if you want any authorized user to be able to pose comments, check the "Post comments" check box in the Authenticated User column.  And if you want only editors to be able to post book pages, Check "Post book pages" in the editor column and NOT the Authenticated User column.
Click the "List" tab at the top of the People overlay, next to Permissions.
Find the user accounts of everyone you think should be an editor, and add that role to their account.


If you have a lot of users already, you can add the role en masse by checking the box next to the names you want to grant editorial permission to, and then pick "Add a role to the selected users - editor" from the drop-down box in the Update Options part of the overlay.