I want to point out that I think a small part in the why reason why Empire ranks higher than SW on every single movie site out there is due to more people seeing SW.

An example of what I mean is:

Let's say a guy watches the original Star Wars and hates it. Maybe he rates it a 3/10. Since he hated the original SW so much, he never bothers watching any of the sequels. Star Wars rating is hurt by this low score, where as Empire's rating is left untouched because the man doesn't rate it because he never saw it since he hated the original so much. I'm guilty of this sort of thing. I hated transformers, so I never bothered with the sequels.

I also think the rankings of Empire and SW is a generational thing. I think older people who saw Star Wars when it came out in 1977 have an attachment to it that they don't to the other films, which is understandable. That said, a younger man who watches them on DVD doesn't have any attachment to one over the other, so he judges them on strictly the film's merits, and doesn't let nostaglia cloud his judgement.