I'm surprised no one has talked about DeadSpace. It's an amazing game both visually and gameplay wise. The story is similar to System Shock and if you haven't played that game then... you're missing out! It's a simple story but very effective. A group of engineers are called to inspect unknown technical problems that have been occurring in USG Ishimura Starship. They encounter problems of there own with there ship and try to land safely into the starship, but once they arrive they realize that more than simple technical problems have occurred. Creatures appear and attack the group. All but one engineer remains, Issac.
Your role is to investigate what has happened and locate the remaining survivors that have relayed the message, while trying to survive the numerous creatures searching for remaining survivors.
And if your not much into the story then believe when I say you will be scared out of your mind with all the suspense (obviously in the right conditions, ie: in a dark room, and solitary)

. All in all, it's a really good game.
CHECK IT OUT!