You guys are creepy. Unless your kids are younger, you shouldn't be spying on them. What if they want to do some research about their health or about something they are uncomfortable with you knowing about?
You can teach them where they should and shouldn't be on the net and whatnot, but logging where someone who is 13 or older has gone is downright creeptastic if the person is personally identifiable, which in this case they are.
Same thing for IMs. Those are private information, and shouldn't be logged by anyone other than the participants in the conversation. Plus, logging IMs of someone else is just downright goofy, because if they want to say something and they don't want you to know it, they can just pick up the phone or talk to someone in person and there would be no record of it.
If they want filtering and know how to bypass it then that's OK (under 13 should probably have it but still know how to bypass it), but if they don't then its not and is an invasion of privacy and freedom on the internet.
Where you go is not public information, it is aggregate logs on huge ISPs and webservers and Google who handle millions of accounts doing billions of requests and aggregate the data in a non personally-identifiable way.
Yes, Google has all the email and searches of most power users, myself included, but there really isn't a privacy trade-off there, as it is probably more secure than most email services.