Worried about the amount of information you have stored in Google services? Fear not. Just launched today is Google Takeout --- which allows you to take a local backup of (so far, some of) the information stored in several of the Google services.
It's not yet full--featured: it only allows backup from Google Buzz, Contact and Circles, Picasa Web Albums and from your Google profile. But the Data Liberation Front promise to add the ability to back up other Google services over time.
This is their blog post announcing the service. Remember: backup early, backup often.