Johnnny Obama
Johnnny Obama voted up Goaty McSheepson's answer
What is a good Xbox 360 game with an interesting plot and long campaign?

I would recommend Assassin's Creed II, Assassin's Creed Brotherhood and Assassin's Creed revelations.

This is because I haven't played the first one, didn't like AC 3, only liked the shanties from Black flag (storyline and graphics were good though). If it were out of 360 (which I don't think it is) I would also recommend Syndicate.

Johnnny Obama
Johnnny Obama voted up Goaty McSheepson's answer
What is a good Xbox 360 game with an interesting plot and long campaign?

I would recommend Assassin's Creed II, Assassin's Creed Brotherhood and Assassin's Creed revelations.

This is because I haven't played the first one, didn't like AC 3, only liked the shanties from Black flag (storyline and graphics were good though). If it were out of 360 (which I don't think it is) I would also recommend Syndicate.