These are singleplayer modules, but they are very much worthwhile:
Elegia Eternum - voiceacting, original music, excellent story. Not much roleplaying, but it's an excellent interactive novel-esque module.
Excrucio Eternum - sequel to the above module. No voiceacting, but still has original music. Plenty of roleplaying options and the story is as good as EE1, if not better.
Bone Kenning I: The Art of the Thanaturge - uber-good. Creative scripting, good story, good roleplaying choices. Mostly geared toward neutral or evil.
Check NWVault's Hall of Fame. There's a lot of good stuff there, and I have only played a few of them.
