Vader's breathing sound was actually scuba diving sounds recorded by Ben Burtt.
Darth Vader is such a complex character that it took 6 people to play him.
Jake Lloyd (Anakin as a child)
Hayden Christensen (Teenage Anakin)
Dave Prowse (Vader body)
Bob Anderson (Vader stunts)
James Earl Jones (Vader voice)
Sebastian Shaw (Old Anakin)
3 separate suits were used over the 3 movies. Possibly another one for Episode III.
It has been rumored that George Lucas wanted Orson Welles to do Vader's voice.
Vader means "father" in Dutch.
According to Dave Prowse, the costume weighed about 40 pounds.
Dave Prowse used to be called Darth Farmer on the set because of his accent.
Dave Prowse didn't know James Earl Jones did the voice until the premiere night of A New Hope. Rumor is that he was very angry. Can't imagine why. ;)
Prowse was unaware of the unmasking scene until it was already filmed.
Prowse had to take his helmet off every 3 minutes in the carbon freezing chamber set of Empire because the steam coming from the floor made the costume too hot.
Prowse used the line "Obi-Wan killed your father." during filming of Empire so that the real answer would not be leaked. The correct line was re-dubbed later by James Earl Jones.
In early scripts of The Empire Strikes Back, Vader's throne was in a fiery pit.
Originally in Return of the Jedi, Vader was to go to his castle on Coruscant to feed his pets. This castle was called "Bast Castle".
Ralph Mcquarrie designed the Vader mask.
George Lucas in an interview said that Vader was based on the character Hakaider, villain from a superhero TV series titled Jinzo ningen Kikiaida from Japan in 1972.
