This is a video created by Mr Sunday Movies featuring all of Darth Vader's kills throughout the movies (including his life pre-Darth Vader in Episodes 1-3). Is it accurate? I have no clue. Does 25 sound right? I hope not because this video says there's 60.
Hit the jump for the video, then argue.
Thanks to YellowWheels, whose kill count remains at 0. That's a good number.