Simple properties

What do you prefer?

1)

private int m_foo;
public int Foo
{
   get { return m_foo; }
   set { m_foo = value; }
} 

2)

public int Foo { get; set; } 

3)

public:
 property int Foo;

The first is C#, the second C# 3.0 and the third one is C++/CLI