-- Last Updated: Oct-06-12 8:31 AM EST --
Very first thing, you haven't indicated how much time you have spent learning self-rescues, including ones like the Cowboy that do not involve paddle floats. Do that now and find a pool for over the winter if you are north.
VHF - get one that can be mounted on the PFD with a good submersible rating and a good weather alert feature - one hardy enough to hear clearly rather than glorified static like the cheap ones. If you are messing around outside of harbors learn how to use it to give securite alerts when crossing channels if needed. I'd put this ahead of a PLB.
Also food, at least snack bars and fluid. And a bivy if you plan to get far enough out that you may have to hole up away from your launch point in a change of weather.