I don’t know if this is definitive in any way, but the Libertarians use this quiz to determine where people fall politically based on their views.
It’s more of a X,Y axes thing, with one axis being belief in personal freedom, and the other economic freedom. Interesting at least. Give it a shot.
http://www.theadvocates.org/quiz
Here’s how I scored (shrunken screenshot) …
{2010 edit: replaced link to application file self-hosted. This quiz can now be found throughout the web and on facebook}