User blog comment:JN273/Weekly poll/@comment-76.25.105.146-20111106001137/@comment-4552472-20111106001554

From what I've seen and heard sneak attacks without a specific perk, do a standard 2x damage (maybe even 10x damage, if attacking from behind, but not sure about that). With further sneak perks one-handed, daggers and bows get better sneak bonus. Two-Handed sticks with the normal 2x sneak damage.