When it comes about keyword suggestion tools, everyone recommends the Overture tool or WordTracker. But how about Google's tool?
You can access it by going to the Google AdWords pages (by clicking on the "Advertise with Us" link): create a new AdWords campaign (or let's say pretend to make one): on the campaign ads there is a "Keyword Tool" called Google AdWords Keyword Suggestions. It doesn't give precise information as the Overture tool, but I think it gives very good ideas of what people are searching for.
Did anyone use it for real, to optimize a web site using it? Do you find it reliable or not?