I'll agree with the previous posters who touted Atonement, Time's Tide on Bright Sands and All Roads Lead to Rauxes. Here are some others I liked:
Retribution and Here Comes the Sun are good investigative mods, similar to Atonement.
The Voice of Reason was a good two-rounder with primarily investigation in the first half, and some good combat in the second half. I liked the interaction with the Rhennee (I have two characters who are Rhennee, including the one I ran through this adventure). Some good plot twists.
Desecrators of the Lord's Tomb and Return to the Undercity also were fun with some unexpected twists, and one in Undercity that was expected. (**Mild spoiler warning**) My home region is the Bandit Kingdoms, and I played it with a bunch of other BK characters. When one NPC offered us a less-than-legal job and asked it we would take it, we said, "Sure, we're from the Bandit Kingdoms. We're used to those sorts of jobs." But we expected him to double-cross us, and when the expected double-cross came, we were ready and defeated him and his henchmen. We captured him for questioning, and the first thing we said was, "We told you we were from the Bandit Kingdoms. That should have been sufficient warning for you not to mess with us."
The Bright Sands mods are all pretty good, except Phantoms on Bright Sands, but Time's Tide was the best of the bunch.
I also enjoyed Clipping Wings.