While Eidos Montreal has impressed me with the stealth in DX: Human Revolution, I'm still cautious in my optimism about this title, but if they manage to get the world and atmosphere right and provide a creative variety of mission types I think I'm really going to like it.
Thief & Thief 2 are two of my all-time favorite games and are on the list of the very few games I bother to replay regularly. I don't think I've ever seen a better example of level design than Thief 2 and the general atmosphere of the whole series is still better than 99% of the games released since the first was released. Thief has a lot of unique elements that should return in the new reboot. Which ones do you think are essential to the Thief experience?