With a short put high quality campaign and a fun, impressive online experience, Halo 3 is worth it.
The campaign is a very fun and interesting campaign, that makes you want to see what happens next. It includes an unforgettable ending and is deffernetly worth playing again (It also includes 3 different difficulties and achievements can be received from all three if you complete them all!) Online is probably the main reason for buying Halo 3, in other words if you dont have xbox live dont get Halo 3, it will be a waste of time! There are new weapons, new cars and even new enemies to face.
The graphics are beautiful, especially the environments and the chief himself. The only problem i had with the graphics was the people, the faces were messed up and they didn't exactly look good (but I got over it, they looked good on the video scenes.)
Everything else in this game is perfect, if you forget about the short campaign and the graphics on the people. So overall; Halo 3 is a MUST-HAVE for any xbox360 owner and will keep you busy for about 15-20 hrs.