I've chosen allow Google to synchronize information from my email to my phone, but the result is not as interesting as it sounds! I see some pictures in the Gallery that I wouldn't have in my phone, ...
I have an ADP1 running 2.2.1, and used it with my Google Account. I have to give it to a friend, and want to erase all my personal data viz. email, chat logs, photos in the gallery synced with picasa, ...