Although I voted (for LotR), I don't think that this is really a fair poll. I think someone has already brought some of the points I getting ready to make up already... But, I want to flap my gums.
SW is very loosely an "original story" in the sense that it was written to be a movie. LotR, on the other hand, is an adaptation of a literary work that (from what I've heard) was never intended to be adapted into film.
SW is also extremely uneven as a trilogy. Although I will always love this material, I'm not a slave to nostalgia. I am well aware of the massive adjustments in quality of storytelling (I'm not concerned about the fx) that SW experiences. We go from a very clear "fairy-tale" type of presentation in ANH to a rather brooding drama that has fairly consistent characterization to something that falls apart as the film progresses. Part of this stems from inconsistent directing and writing. Lucas is a great conceptualist, but not the best director nor the best writer. That's why TESB is typically considered the best of the original three... he didn't have his hands all over the story. RotJ is horribly derivative because Lucas reinvolved himself in the process and robbed people of what should have been a truly spectacular conclusion to the story. I can say that the ending of the SW trilogy did not evoke the same emotional response as the end of LotRs... and I'm far less emotional now as a 30 year old man than I was when I was 9.
But, this gets back to the nature of comparing these two films. Jackson had the unenviable responsibility to take an established text revered by legions of (sometimes rabid and blindly devoted) fans and adapt it for film. He could make changes... but only so long as he adhered to the general spirit of the source material. He couldn't really change all that much (and considering the relatively minor changes and the almost infantile tantrums some had over them, it's a good thing he didn't do more). Jackson was working with a prepackaged product. Lucas changed stuff as time went along because what he really had was an outline, not a full-fledged story (and I'm convinced that as time progressed, he adjusted stuff in order to grow his young fan-base and mass market appeal. Afterall, ewoks will sell a lot more toys that wookies).
Thus, SW is unbalanced (and this lack of equilibrium has become even more apparent with the release of the prequels) as a trilogy while LotRs is not. LotRs is more successful as a movie trilogy. But, in making this assessment, one must take into account the foundational differences between the two.
That said, I love both trilogies. Unlike other SW fans, I'm willing to recognize the gross flaws in the movies... but I still enjoy them because they had an impact on many of the things I love today. And I love LotRs... even in spite of not being fond of some adjustments and sacrifices that
had to be made for the screen. These are two series that deserve to be respected and revered for their impact not just on speculative fiction on the silver screen, but for their relavance and positive influence (aside from some marketing elements) to popular culture.