Lair of the Shadow Broker(In fact most every major DLC from Mass Effect, Kasumi's mission was awesome.)
Shivering Isles
Most of the New Vegas DLC
CDPR's free expansion of the Witcher 2.
Valves releasing new n4d campaigns for free and retrofitting old ones.
Daystar Clarion said:
I consider Dead Money the weakest of the bunch and it's still a solid bit of DLC compared to most.
I don't understand this. Dead money was the best of their DLCs. It has a very interesting theme that was nonstandard for videogames; which it presented remarkably well. It has the most interesting characters with the most colorful back stories by far; and it lets you interact with them on a level that none of the other DLCs approached.