How Far Should Openness Extend?

If you could open one of the following data sets tomorrow, which one would you open and why?

All non-classified government data

Census information

Government statistics

Geo data

Weather data

Public records

Data from publicly-funded research projects

Digitized books and media from public libraries

Selling the idea of open data seems straightforward. If taxpayers paid for it, a government should share it. But there have to be exceptions for National Security and privacy.