There will always be a select few movies that I will neeeeeeeeever get sick of, no matter how many times I watch them.
The Princess Bride is one - I must have seen that twenty times now. It never gets old. Chicago is another, and so is Amelie.
I don't know what it is about certain films - some just manage to hang onto their initial spark, even if it's the hundredeth time I've watched them. Which is why nobody ever asks me what film I want to watch - they all KNOW what I'll suggest, and most of them will be sick of it, heh.
I can't help it if I have favourites!