Stunning visuals, and it delivers on its promises.
The story line is intriguing (though I have not finished the game). Assassin's Creed is just the first of a trilogy so I expect some of the storyline to carry over into the next game (as I have seen complaints about an unfulfilled ending).
For me, this game shows only the tip of the iceberg of what is to come out of the next gen game systems. A huge, completely interactive environment with hoards of NPCs and a smooth gameplay is just the start of what is to come onto the next gen systems.
Overall, Ubisoft has managed to deliver on all its promises for the game. For those who have been anticipating this game, you will not be disappointed.