Well, I'm not really that nit-picky when it comes to the movies... but I guess I have made comments about the Hobbits' hair color. Frodo's is great, but I thought that the other's were too light. I was mainly irritated with Merry's, but that's also because I thought it was too light for Dominic Monaghan's complextion. Haha... talk about nit-picky!
But, hey, some of the best jokes and parodies come out of nit-picking