Storm was African-American instead of African. Colossus was American instead of Russian. Wolverine had never met Sabretooth. Wolverine was also a foot taller and did not use any Canadian slang (eh, o, bub). Cyclops, the unquestioned leader and one of the most central characters of the X-Men, was a side character and not very assertive as a leader. Iceman was never some young kid, he was an original X-Man, he was not so much younger than everyone else. Mystique could never fight like that and Wolverine would have kicked her ass with ease. Rogue was actually the character of Jubilee, they just called her Rogue. Pyro was not a kid. Sabretooth was not just some growling idiot. Lady Deathstrike was not "just like Wolverine", and did not have a healing factor. And the list goes on. I think this validates my Simpsons comparison.

So you can see how I would have a problem with the casting as well. And compared to Iron Man and Batman Begins, there were a hell of a lot more changes. Who could they have gotten to play Magneto better than Ian? I don't know, but Chuck Norris is 70 years old, not that I'm suggesting him, and he looks damn good, so they could have found somebody. Point is, it was way to loosely based, in light of other movies that have been more accurate. But, I guess we will have to just agree to disagree, because you don't seem likely to be convinced otherwise.