Halo 3 is the best single-player Halo ever, about 80% of the game is quality (the other 20% being the final 2 stages of course). Plus the sales for the game were astronomical, I have no idea how anybody could call it a failure of a game... though I know of at least a few people who prefer H2 in multiplayer (and I'll admit I'm more partial to some of the H2 maps).