Data Privacy: ending dependency on google?

It seems to me that most efforts to secure privacy on Android concentrate on the on-device apps and encryption of protocols such as SIP and IM. I've found it nearly impossible to use an Android phone without turning over a significant chunk of one's data to google, though. Particularly calendar and addressbook data. Europe's branch of the Free Software Foundation touches on this briefly under "Synchronizing Your Data".

I've been looking into setting up a Kolab server for this, and even entertained the idea of setting up a shared / cooperative server for others who are interested. I'm wondering what other solutions people might recommend, or any other thoughts on this topic you folks might have.