As much as I like Hugh Jackman's Wolverine, I don't feel like they really play the characters. They play themselves, with notable traits of the characters. I feel like it is done to make the characters more attractive to the general audience. RDJ's Tony is just too damn likeable.
Evans, Hiddleston, Hemsworth, McKellen, Ruffalo, Bale, Cavil, Garfield, McAvoy, Reeves, and Keaton are the actors who for me have most brought their comic book counterparts to life.