Hmmm well I've seen:

Lord of the Rings: Fellowship of the Ring, 5 or 6 times, am not sick of it yet!
Lord of the Rings: The Two Towers - 5 or 6 times, am not sick of it yet!
Lord of the Rings: Return of the King - 4 times
Definately not sick of it

So those are some I could see over and over. I can't think of anymore at the moment.