If you're the sort of player who prefers stealth over confrontation, Thief may just be the next game you want to look into. Apparently, Eidos Montreal's next-gen reboot of Thief will include a mode catering to players who like sneaking more than fighting.
According to Thief lead level designer Daniel Windfeld Schmidt, this mode, when activated, will disable certain elements on the HUD and nerf Garrett's special abilities a bit. This means you'll be sneaking around without notifications, markers, slow-motion attacks, and whatever other conveniences the conventional mode will have.
Sounds pretty rough, but as they say: no pain, no glory. Besides, similar titles such as Dishonored give stealth fans the option of not being homicidal maniacs, and it's certainly satisfying when you realize you've beaten a game without killing anyone (or at least committing minimal murders).