Do you have content in both DocBook and DITA? Are you worried that it has to be one or the other? Two doctypes means two stylesheets, right? It's not as bad as you think!
If you've been following the teachings at the Dojo and using best practices, you're already using modular stylesheets.
In this session to find out how you can toss up a new stylesheet for a new doctype in a matter of minutes!