Ico was one of the most "epic" games I'd ever played, at the time. The only thing that was in the ballpark was Ocarina of time, which while much larger, was made up of several smaller connected areas. Everything in Ico was connected and open - very few loading screens. When you would look off into the distance and see other parts of the castle, it just felt very open and amazing.
Okay, all this talk has me getting a new avatar. Woo!