Which one was the longest? Point Lookout. Unless you only feel the need to do the story, if that's the case, you really shouldn't be playing this game.
The most interesting? It's a tie between The Pitt and Point Lookout.
The Pitt gives you a story that outdoes Point Lookout. That, and the new weapons, armor, and (probably one of my favorite things) the ammo press.
Point Lookout gives you a story... Well, honestly it's a great story. It'll stick with you for a long time. Lacking a good selection of weapons and armor, though. But then you are
allowed to explore. Something many people wanted from the previous DLCs. If all you do is finish the main quests, it may last you two hours, which is the norm for Bethesdas DLCs. But, if you decide to explore. Not only will you get one of the most fulfilling experiences in the game, but hours more of enjoyment.
The most added to the game? Broken Steel. No contest. It changes the ending to let you play longer, raises the level cap, adds more items, weapons, enemies, places, and NPCs.
And overall the best add on? Broken Steel. For the reasons above.
« Last edited by Reverb on Feb 1st 2010 »