Hmmm. Interesting. So many good games. :) I've already played Deus Ex: Human Revolution, Dishonored, Hitman series and Splinter Cell: Blacklist. I liked them all. Absolution, not so much, as it lessened disguised gameplay and focussed more on regular stealth.
I guess I should try Mark of the Ninja and the Thief games. Haven't played them yet.
Thief and Splinter Cell Chaos Theory. Only two stealth games you'll ever need.
Uh, which Thief game should I play?
Thief Gold and Thief 2: The Metal Age.
Thief 2 is the best Stealth game ever.
Play on Expert, otherwise it's not true Thief; that gives you all the objectives and such.
I'd advise you get the GOG versions though. The Steam versions are the GOG versions actually are the GOG versions; but to install the unofficial patches, yu have to install the games with Steam, then copy the game folder to somewhere besides Program Files, then patch the copy there. The patches/mods won't work if Steam knows where the game is or it's in Program Files. So GOG is just easier as it installs to C:\GOG Games and you can mod it freely.
Console war in a nutshell: http://imgur.com/xA6GJZ9