Public vs Private (vs Protected)

Alright /prog/, do you prefer to default your class' members to public or private and why?

class dude : person {
public:
　　int var1, var2;
};

or

class dude : person {
　　int var1, var2;
};

>>3

Yes, public, private and protected all have their own uses. However, the question remains what one should use as a default for good practice when any in particular would work just as well.

Also, I've used Ruby. It's pure OOP and doesn't have the shit syntax of smalltalk.