In my experience blogger really does seem to have the edge over wordpress. Marisa is right that this should not be the case, but all other things being equal, I have seen it happen.
I haven't tried typepad. One factor to take into account: typepad is harder to get out of. You can easily export your blogger content to start a self hosted (wordpress) blog, not so easy with typepad.
Ultimately I do agree with Marisa that having your own self hosted blog is a good idea, but if you haven't found yourself a niche yet, go with blogger: it's a good place to get your feet wet.