The New York Times, in its "Room for Debate" series, has a "discussion" on the deletion of the words "nigger" and "injun" in a new edition of The Adventures of Huckleberry Finn, replacing them with "slave" and "Indian." The question The Times asks, "Is there never any justification for altering a classic?" seems rather jejune: we alter classics all the time. Not only that, it avoids the question, just what is a classic anyway (though one of the discussants does say that the book is just as well not read).
Each time we use Van Gogh's "Starry Night" for a screen-saver, we are altering it. When Michael Steele says his favorite book is War and Peace then misquotes (as though they come from Tolstoy) the first lines of A Tale of Two Cities, he has altered two classics.
One of my favorite alterations of a classic is Marcel Duchamp's, of a postcard of the Mona Lisa. An alteration of an alteration:
What's important here is that Duchamp never claimed his changed postcard as the Mona Lisa.
Sure. Change Huck Finn all you want--after all, it is in the public domain.
Just don't call it Mark Twain's Huck Finn. Follow Duchamp's example.
In this case, make it The Adventures of Huckleberry Finn by Alan Gribben, the man who suggested the changes.
As to whether or not one should use the unsavory words themselves, see that Times discussion and decide for yourself.
As to what's a classic... well, the World Series is sometimes called the "fall classic," and that's classics enough for me.
Update: For a good discussion of the implications of the change, check out this post on Daily Kos.