I'd Agree with Orion on this, and go one step further and say the theme the set is sold under primarily, either from the catalog or the online store if no theme is on the box. Simple is better. Keywords can then be added to clarify for searching. Bricklink, Brickset, and Peeron all have different theme trees.
- Greg
"The only stupid question is the one that remains unasked"
"The only stupid question is the one that remains unasked"