In reference to Burnett's comment, I would strongly vote 4x3. I'm not interested in seeing actors' shoulders and tops of heads cropped out of the frame.
Just hit the zoom button on your BD player and see how long it takes before it gets irritating.
15 years ago, consumers had to fight ignorance and stop studios from cropping 16x9/scope movies to 4x3. Now we have to do the opposite and fight ignorance on cropping 4x3 to 16x9.
Is it 'fair' to today's audiences that movies like Casablanca aren't available in 16x9?