Twain was powerfully against slavery. Huck is an innocent whose treatment of Jim is problematic (after all, Huck is a product of the world that raised him) but ultimately profoundly humane. Twain creates Huck at the intersection between received social practices on the one hand, and innate innocent humanity on the other. Given the mythology of America as the cultural innocent faced with the complexities of the world (see Innocents Abroad), Huck is an avatar of America. Hemingway, also banned I see, once said that all American literature flows from Huck Finn, and I think he's absolutely right.

About the N-word in Huck. Not to use it, or to edit the text so that it disappears, is to falsify the history of this country. The political equivalent is Sarah Palin's idiotic statement that the Founding Fathers worked to get rid of slavery, when in fact they enshrined it in the Constitution. To my mind, erasing the past is a much much worse problem than facing it squarely. Yes, this country was built on slavery. Yes, this country struggled mightily to get rid of slavery. Yes, we're still struggling with the consequences of slavery.
MACTECH ubi dolor ibi digitus