I voted FOTR.. it has the best rares ever and a lot of combos to be made (rainbow deck creativity).
It was few cultures, but as the starting expansion it introduces very well each culture's flaws and advantages, and their mechanics. And as mentioned before, those cards are still very usable for movie block decks.
Still, FoTR (the block) was a great game.
It beats TT by far because in TT you mainly double-move and there's not much control for decks with a lot of companions. Plus, you don't get to extra-think how to restrain or add twilight any more.
And it beats RoTK because of stupid
Galadriel LR which makes it hard to well-plan a shadow deck.
Maybe it's because I'm more fond to killing. Im more of a shadow player..