Who chooses what aspect ratio to use?

[Canada]

This is not another why the hell are there black bars on my widesceen TV thread. I watched all the Lethal Weapon movies lately. Which got me to thinking Richard Donner did the original 1978 Superman (and yes I know there is a Richard Donner cut of Superman II) in a 2:35:1 aspect ratio. Skip ahead 9 years to 1987 and Lethal Weapon comes out in an aspect ratio of 1:85:1, what gives? I like the more spacious feeling that the aspect ratio of 2:35:1 brings to movies, especially action films, I just feal that directors can better convay action scenes.