I just finished The Forsworn Conspiracy quest yesterday - and I have to say - one of the best quests I've ever played in years of RPG gaming. It was satisfyingly long and didn't require that I kill an entire dungeon of enemies. The voice acting was great, particularly the King of Rags. I was deeply immersed and when it came time to pick a resolution, I went against my Nord heritage.
I really like how there were no innocent people and no easy resolutions. I've seen this again and again in this game, and I'm really enjoying that quality.