So let's talk about Fallout: New Vegas.
I'm only about 10 hours in, but I'd say it stomps Fallout 3 already. Obsidian brought back a lot of stuff from the first two games (Traits, the Survival skill is back), there's more of an emphasis on crafting (you can create herbal remedies and you can craft your own ammo), and the writing just seems better.
Also, take the Wild Wasteland perk. Do it.