Original Aspect Ratio always and forever...the main reason I don't watch movies on network TV.
Since I consider movie making an art form, I want to see it how the artist intended me to see it. Would it make sense to buy an expensive painting and trim it to make it fit your frame at home? No, of course not.
Couldn't have said it better myself, although I can appreciate the OP's point of view as well.
For OP, I'd say use zoom. But I also think that OP should check out some of the websites showing the difference between zoom and Original Aspect Ratio shots. For 95% of most movies, there's no real difference, but for the other 5%, it's all the difference in the world.