After exposing the filter in views, we can configure it as follow such that it will automatically add an <Any> option in the selection list and display all values when the view is first rendered.

 

Make sure the followings

• Operator: is one of
• Options: uncheck all (Node Type in this example)
• Optional and Force single are checked
• Remeber and Link list to selected items are unchecked

Done =)

Reference:

• realguess – Views Exposed Filters Default Choice
• Drupal Support – setting views exposed filter default to <any>