A study from Privacy International has found that Google is "achieving the status of being an endemic threat to privacy." Issue with Google included:

• Failure to provide an expungement option for retained data
• Failure to follow generally accepted privacy practices such as the OECD Privacy Guidelines and elements of EU data protection law
• unstated or indefinite length of time for data retention, without clear limitation on use or disclosure

I don't care a bit about the second point, but the other points could be of interest. But it all depens on what data you want google to have, a factor you have great influence on, although lots of people like to use their services and than play the innocent idiot saying he didn't know that. I know nobody does it, but one should read the terms and agreements of any account one subscribes to and handle one's data with care. I am a heavy google user, but there are data I do not keep in google in anyway, as far as I can control. Use your head, I like to say.
At the same time, I'd like to know who Privacy International is before I believe anything they publish.