One word: "Yipes"
(No, that is not my first word choice, just the edited for TV version)
I loved Halo, I enjoyed Halo2 (even though the game and storyline seemed too short). I'm looking forward to the next installment in the story and another chance to save the universe.
As a side note, the Halo novels were really well done and give a lot of background into the story line. If you ever wondered where Spartans came from, read the first book.