I totally agree. When I first played Metro 2033 I dropped it pretty much instantly as, like you say, I was more used to FPS campaigns at the time like CoD and Halo. It was only until I saw a friend playing through that I realised that FPS could be a great way on telling interactive stories. Picked the game back up and got hooked!

Not sure if they're classed as AAA but I'd consider the the Metro games (more specifically, 2033 and Last Light) to be underrated.

They're my all-time favourite games but I don't really see many people playing or talking about them. In my eyes, they are the best form linear story-driven FPS games since Half-Life 2 released!