Hissingsid - 8:45 pm on May 17, 2012 (gmt 0)
The other cookies that are used to inject ads, track visitors etc are not exempt and require opt in by your visitors. They have to give you positive consent to store cookies on their machine.
An interpretation of the law is that you must provide your users with the ability to revoke their consent. Amusingly the ICO website does not have this option in their solution (at least when I last looked a couple of weeks ago). The fancy BT solution allows the user to control which categories of cookie they will accept. But if you look the essential ones cannot be blocked.
Hope this helps
PS Unless the ICO say it is OK to not ask for consent to Google Analytics cookies by the 26th I'm pulling GA code from my pages on the 26th. I'd rather fly blind than have my users confused.