I think the whole debate over Pluto's planet status is ultimately pointless - In our solar system there are exceptions to every rule:

Asteroids that exhibit comet-like behaviour at perihelion ( Chiron ). Moons that are large enough to have been planets in their own right, but were captured into retrograde orbits ( Triton )
Failed stars ( Jupiter )
Captured asteroid moons ( how many now at Jupiter? )
Moons of asteroids ( Ida / Dactyl )
Dead comets ( Icarus )
Binary planets ( Earth / Luna )
Binary asteroids ( Toutatis )

etc etc etc

Pluto is a planet in every book you care to mention, and the aye's have it.