Hello! I'm new (rookie) to this forum and someone have already probably mentioned this, but anyway:

When Darth Vader falls from the carbonite freezing chamber after fighting with Luke, he originally (in he VHS-version) said "aahh", but in the newer versions he said "oof" and that sound is a copy of the "oof" he said when Luke put some smoke in his face just a few moments before.

Please Adywan, change back to "aahh"! It is more logical to say "aahh" when you fall backwards than "oof"... :-)