Using out-of-the-box SharePoint 2007, I want to create a required "choice" field that has values but no spaces/blanks as a valid option. I then want the entry form to show a blank as you select information on this field, and then validation to fail when no selection is made.
It is quite easy, yet counter-intuitive to do. Just set the default value to blank, even though there is no blank option in the values you are using. Pictured below.