For me it goes like this:

Original (unaltered) Trilogy trumps all

Original Radio Series comes next

Heir to the Empire trilogy is the only expanded universe I recognize.

All else isn't canon to me, including the prequels as they are trumped by the Original Trilogy on numerous points of continuity.

There are plenty of Star Wars stories that I enjoy, comics, games, edits and what have you, but nothing else I would consider canon. To me all else is "inspired by" Star Wars as opposed to being truly *part* of the Saga.