Love It! Rated 5 out of 5 stars

Update 10/14/2009:
I've created an about:me toolbar button.
Nice work on getting this going. I was wondering how well this would turn out and it's quite cool and I think it will be a great feature when it becomes a default one in Firefox.

I'd like to see specific date ranges added or at a minimum the days of the week for all activity not just downloads unless that is already available and I'm just not sure how to view it.

I may also be overlooking this too, but aside from manually typing in about:me, I see no other way to bring up the page. I know that most people won't want another toolbar, status bar button, or Tools menu item, but it might not be a bad idea to offer one of those for people who would like a way to access about:me other than having to type it in.
I've simply bookmarked it for now. I prefer to just use about:blank for new tabs. Perhaps I'll set it as my home page later.

I'm looking forward to updates.

This review is for a previous version of the add-on (0.4.1).