Not overrated, but not a game I'm going to play for a year.

User Rating: 8 | Halo 3 X360
I bought Halo 3 after playing some short multiplayer matches at my friends'. I got pulled into the story line of the single player which is really gripping. But the multiplayer never really pulled me in further. It seems to much like multiplayer games of old.
However, the multiplayer campaign play looks pretty cool, but I do not see myself playing this game again and again which is what you would have to do.
If you are only a single player fanatic, then it's a good game and good storyline. It's definitely not overrated like some may suggest, but not a game you are going to play and replay for a year. The single player gameplay is not difficult - I played through pretty quickly on Heroic. I had no desire to replay though, so I cannot say how difficult Legendary would be.

In that way, it is only an "8" for me. I assume the people that give it a "10" are really into the multiplayer or uber-Halo fans - either of which would get the replay enjoyment out of this game that I do not.