Book vs. Movie characters

I think that for the movie, the Elves in Helms Deep was great. To me it seemed romantic that the Elves should stand and fight with men one more time before leaving Middle-Earth forever. Even though it was completely implausible in the book. At first when I watched TTT I was horrified!! The changes were huge!! Every time I watched it and Sam would say "... we shouldn't even be here..." I would shout out loud "Darn straight you shouldn't!" But after I watched the Extended Edition and the writers explained why they had to make such changes I felt better and realized that the movies are in reasonably good hands cause all of the writers and PJ care about the book and are, like us, fans.