How to Choose a Pre School?

Been wondering what are the most important things to look for when choosing a pre school. Understand it will be very dependent on the child and her or his needs. Of course, am interested in imaginative art projects (open ended), music, maybe some dance and a lot of interacting with peers. Know I like the idea of child directed play.

Just thinking about what to look for when observing classes. Anyone else have any ideas or expriences?