When I first played Dead Money I was pretty much rushing through it, didn't take my time and only sort of payed attention to the story. Yeah didn't enjoy it as much.
But when playing through it a second time, I took my time, read the terminals and the history, listened to the dialogue, and I gotta say, Dead Money is probably one of my favorite DLCs period. I love story-driven DLCs, and this is one of the few DLCs that actually made me think about what to say, what actions to take etc. Especially when it concerned with certain characters like Dean Domino and Dog/God.
The companions felt alive, and the antagonist did too. Father Elijah was enjoyable because he relied on his wit and intellect more often than not. Antagonists like Alduin are boring (to me) because of the fact that you have to beat them in pure strength, and the dragon's case pretty much let the 4 heroes do the work. But Elijah? You don't see him until the end, and even then you don't even have to fight him to beat him.
Don't get me wrong, Dead Money is flawed and has its kinks that need to work out. The whole radios thing irking the hell out of me in some cases, but in general it was one of the better DLCs I've played in a long, LONG, while. Bethesda and Obsidian, if you're reading this, please PLEASE make DLCs with as much detail into the story and characters like Dead Money did.
Environment: Great
Story: Excellent
Gameplay: Good