I found BioShock really enjoyable. It's colourful character designs, set/scene mechanics and audio/sound effects are what brought me to the creepy underwater Sci-Fi Action Thriller.
The cutscenes and cinematic approach to a world that seemed to have advanced below the surface by Scientists, Rapture seems to be the first stop on your journey in this amazing trilogy (I've played this game before the second game came out!).
Then you hear the "simpler times" style of music playing in the background and you feel "Oh, everything is OK."; yet nothing really is in Rapture. "No Gods or Kings, only Man." says Andrew Ryan of Ryan Industries, at the beginning of the game. Lush dark moody scenes to colourful, vibrant energetic scenes are what gaming is truly about.
Seeing characters willing to risk everything to take you out, then you back out of an area and suddenly, the enemy has found you yet again, the AI really had me on edge at every moment and I believe this game should be (at least the first game!) should at least be in every gamer's collection at some point in their life.