I voted for Arkham Asylum. Not only is the voice acting, combat, music, and atmosphere top notch, but what really sets Asylum apart is the metroidvania elements and the sense of dread the game gives you. It's not an open world game the way City and Knight are. It's a series of very closed spaces with just a few kinda open areas, but you can run from one to the other in like a minute lol. You're a lot more focused on the detective aspects of Batman to continue through the story, and it was all just so well done.
I'll never forget the first time when I was playing and the game made me think my game just crashed reminded me of Eternal Darkness.