There's a tool to control the pressure response curve of your tablet:
http://www.lab.envirex.cz/?page_id=3
This lets you do things like lower that maximum force necessary to achieve an opaque opacity (without having to press real hard with the pen). You just need to study the graph a bit to know how it works.
Make sure to run it with administrator privileges.
The Intuos Pro models come with such a tool officially, in the configuration dialogue.
The Bamboo models -- I guess they're called Intuos Pen now -- being cheaper, don't have this. They do support a pressure curve hidden inside the configuration file though, which is what that third-party tool manipulates.
