I found this pair of articles that give the most detailed descriptions of the changes throught the many versions of Star Wars and Empire Strikes Back. This is easily the most comprehensive list ever complete with screen shots and audio clips and this guy picked up on stuff that even I, after seeing the movies probably 100 times each in my life, wouldn’t have even caught.
In most cases I’m in agreement with the guy’s opinions on what was good/improved, and what sucked ass. The two things that bother me most of the recent DVD set was the replacement of the spirit of Anakin at the end of Jedi, and the replacement of the dialog during teh scene on Dagobah when the creature spits out R2D2. Oh yeah, and them replacing the dance number in Jedi with that stupid CGI muppet band, ugh! I can’t wait for this guy to write the final installment and see what he says about that stuff.