Fave character in the movie but not the book is a tough one. Now, switch that around and I could give you a list a mile long!
For the original question though: Figwit is pretty cool. I felt bad for him in RotK when Arwen turns around and goes back, and he's just standing there like: " . . . . um . . ." lol And I didn't know that's why he got a speaking part! Hmm, makes sense for PJ and them to check the fansites, but you just don't think about stuff like that . . .
Figwit's my fave (and, Elven-Maiden, I like Arwen's new roles, too!), but I feel compelled to mention someone no one has said before. So: in the very beginning of FotR, during the battle with the Last Alliance, after Sauron is "destroyed" and it produces a shockwave of sorts, everybody's getting whipped around. There's this one Elf, dunno his name, but the poor thing's hair is going everywhere. He looks like he's in a hurricane or something! And I just think that the way the lighting and angle of the camera, etc., is, that's one of the coolest single freeze-frame from any movie I've ever seen! I look for him now, every time I watch FotR. If anyone knows his name, please tell me! And I'm going to be quiet now, because I'm tired and not writing well, and I've already written a novel. lol