Uh oh... that's what I call getting the worst of both worlds!
Vishal, the button reads differently because that has always been a part of Apple's philosophy. 'Choose File' is easier to understand than 'Browse'. Similarly, there are no 'Yes' and 'No' sort of dialog boxes in Mac OS X. The buttons always read 'Save', 'Don't Save', 'Review Changes', 'Discard Changes', etc. instead of 'Yes', 'No' and 'OK'. You, of all people, must have noticed that Microsoft has changed a lot of dialog boxes in Vista to make them easier to understand, compared to XP.