What bothers me most about remakes is just how useless they are. I can count on one hand the number of times the remake was as good or better than the original.
Let Me In was just as good as the Swedish version, since it did some things better (like focusing on the kids more than the neighbours) although the special effects were terrible in the remake.
Some people have said The Departed is better than the original. I've never seen it, so I can't say.
But mostly, they're just terrible. Why not save that money, use a small portion of it to clean up the picture of the original, and just re-release it?
What bothers me more though, are foreign movies remade. Trollhunter, for example, is now getting a remake. Let the Right One In was already a great movie. If people were a little more open minded about movies in another language, we wouldn't need to remake them!
But then there's some that are even in English that are remade, which just makes absolutely no sense to me. Death at a Funeral, for example! A brilliant British comedy that's remade into a generic black comedy. There's talk of an American version of a highly praised Canadian TV show, Little Mosque on the Prairie. Why would they need to remake it?! It's right there in its fifth season! They didn't remake The Trailer Park Boys and that was (I believe) pretty damn popular in the U.S. Popular enough for two movies, at least.