You know, it's funny how the difficulties in Halo 3 vary. First there's easy, in which a brute chieftain attacks you with a gravity hammer and only succeeds in taking away only less than one quarter of your energy shields. Then, on legendary, he skins your foot and you go flying dead. And that's why I play on easy.
EDIT: I never play easy anymore. I'm almost done the campaign on Legendary.