Do a search that finds all contacts (for example, Find Contacts and then search without entering anything), then select "All nnn contacts" and choose Export from the drop down menu. You can select all primary fields or specific fields to export.
This might do it for you or point you in a direction
Create a Group of All Contacts (A)
Create a Group of All Contacts who have ever had a Case (B)
Use the Custom Search: Include/Exclude Groups and set it to A-B