What about Temple of Elemental Evil? I hear it's all the rage in the Giant Bomb blogging community.
You may find me crazy, but I have a second playthrough of that game going on right now, with the new content version of the mod installed. It was going on before I gave you guys the game, but I started in earnest once your little competition begun. So far, what I can say is basically that the new content makes the game significantly easier by giving you some really good items and lots of EXP, and also that having a Paladin in your party is a bad idea if you want to do any of the Temple Faction quests.