I propose a little experiment. Log off your Google Account and try to imagine you're a different person. You're a friend who found the password by accident. Then log on the same Google Account and try to find interesting information about you in your Gmail, Search history, Google Calendar, Google Reader and other services. You could use this page for reference. Try not to think about what you know is there.
How would you describe yourself by looking only at the data? Can you find anything that would embarrass you if it were public?
If you Google yourself, most of the data you find in the search results is hard (if not impossible) to destroy. If you search your private data, anything can be deleted. Would you delete anything if you knew someone would break into your account?