Class declaration

The question is actually more about style.

the class is usually declared either:

class My
{
public: // interface
...
private: // implementation
...
};

or

class My
{
private: // implementation
...
public: // interface
};

The question: who uses which style and why? Suggestions appreciated.
Thanks!


Upd. Also, I would appreciate if you write your style as it looks in code ( see my code above ) + some comments (reasons, additional thoughts). I think maykie's post style is a great example.