THE DARK MOD was once a total conversion of Doom 3, and is now a STANDALONE GAME with the release of TDM 2.0! A dark and moody stealth game, inspired by the Thief series by Looking Glass Studios.
PROS:
-recreates the Thief 1&2 feeling but also boasts some more modern graphics and mechanics
-it doesn't require Doom3 to be installed
-over 50 missions available at the creators site means this mod will keep you busy for a long time
-smart AI guards that react to sounds, dead/unconscious bodies, missing items and know how to relight candles/torches
CONS:
-some of the missions are very skillfully made while others...not so much
-melee combat is broken and best avoided entirely
-initial loading of a level takes a long time
P.S. Don't forget to download and install all of the mods updates as without them the saves won't work.