10. Éomer's braid suspiciously switches from one side of his head to the other.
9. When Gandalf dies, Frodo will look sad for a moment, say "I can't believe he's gone," and then he'll be completely over it.
8. An orc bangs his head on the door while he's rushing into the Chamber of Mazarbul in Moria.
7. The Witch-king will step up to Éowyn and start doing some overly-elaborate sword spin. Éowyn will just look at him, then shoot him with a crossbow.
6. Aragorn keeps saying "It's not my fault!" when things go wrong.
5. Gollum won't actually fall into Mount Doom on the first try. He'll slip and fall and land on a ledge, and Sam will say "Negative. It didn't go in. Just impacted on the surface."
4. Sauron will sound like he is wearing an aqualung and will appear (complete with theme music) dressed all in black with a floaty-flappy cloak. At the end he will reveal he is really a good man at heart and that he is someone's father.
3. All of the bad characters will be spectacularly poor shots who never hit the good guys (which leads you to wonder why they were so terrifying anyway) while the good characters are all crack bowmen/swordsmen/axemen/wizards who could pick the sprinkles off the Witch-kings ice cream from 2 leagues away.
2. Legolas is fluent in over 1 billion forms of communication, but still has to hit Gimli on the head to get him to pay attention.
And the Number One way The Lord of the Rings would be different if filmed by George Lucas:
Additional inscription on The One Ring: "Class of '62"
by Folks of the Main Message Board