Who would win?

One of the oldest questions in mankinds history is "Who would win?". Whether Hulk against Superman or Spiderman against Batman, the discussions on the school grounds (and perhaps also in the offices?) of this world are endless and are likely to continue for all eternity. 

But if you think a battle between the big Green and Kal-El would be epic, how about a fierce fought struggle between two of the most iconic characters of the last decades? In the black corner, powered by dark forces and a red light saber: Darth Vader, right hand (though he's still missing his own) of the Emporer. In the white corner, powered by magic, an elven sword and a wooden wand: Gandalf the Grey (or the White, if you want to stage this fight a little bit later).
So, what do you think? Who would win and why?

If you have additional suggestions for epic duels, we would like to read about them in the comments.