New proposed classification system
Here goes:
Mars class planets: things you can land on
Jupiter class planets: thing that are clearly planets but which you can't land on
Pluto class planets: things too small to be planets but look like planets and are fascinating in their own right
Earth class planets: things you can land on but wish you hadn't once you meet the inhabitants
Space debris: everything else
(Inspired by Miles Kington's "Nature made ridiculously simple")