Short Single Player, Awesome Multiplayer
Cons - Single player may have a great story and good enemies but it is very short, since the online community is so big you get quite a few bad apples with some of the users
Halo 3 is one of my top 10 favorite games. Some of my best Xbox Live memories has been playing Halo with my buds. No other game has as many options, game modes, and maps to play on for multiplayer. Even though this game was released over a year ago still hundreds of thousands of people play it. Just today when I went on live to play it there was 300,000 people playing it. You will never have to worry about finding a game. However if you do not have live I am no sure if this game is worth it. While the story, graphics, weapons, and AI are fantastic the single player campaign is still very short. There are only 9 missions. I would say beating the story mode takes anywhere from 5 hours to 10 hours depending on your skill level. There is not a lot of replay ability with the game. I only beat the entire game twice (once by myself and another time with a friend) and all I do now is play online. Honestly though this game's multiplayer is so good it is worth getting live just for this game.