I'm just about near the end game now. Fallout 3 is, more then any other game I can think of including FO1&2, an archeology game. That is when it's at its best. It does away with the boring stuff that actual archaeologists have to do like cataloging and documenting, it's all about piecing together the story after the fact. You enter these abandoned buildings, vaults, homes; You read their diaries; go through their stuff; check their corpses. Just about every single location in FO3 has a story to tell even if there's no one there to tell it. These little moments are what make Fallout 3 such an amazing game to me.
Right from the moment you leave the vault this becomes noticeable. At the foot of the Vault 101 door you see these picket signs. It smacks you INTO the world of the Capitol Wasteland. There were people here dying and begging for their lives to enter the safety of the Vault as they die at the door.
Bioshock comes to mind with this example. We saw familiar signs right when entering Rapture. All of the other 'Shock' games in fact are similar in this fashion to Fallout 3. You've got the logs, the aftermath of events, the puzzle to piece together. In the Shock games however those pieces come to form the main plotline. In FO3, all of the hundreds of locations and little pockets of stories don't have anything to do with the main (*cough*forgettable*cough*) plot at all. It's ancillary and unnecessary.
A few times, as it happens sometimes even in archeology, you get multi-layered stories. Dunwich Building for example. You have the pre-war history: why it was there, what happened during the bomb, etc. Then you have the post-war history: A tale of a guy going mad after finding a mysterious book. Then finally you have a THIRD later on top of that (minor non-plot spoiler):
Fallout Wiki said:
There is also a log on a terminal made by an unnamed scavenger who wandered into the ruins, hoping it to be abandoned. Upon finding the ghouls he holds up in the room with the terminal and as paranoia sets in he remembers his friend 'Billy' coming with ammo and grenades. Using this cheerful optimism he logs off the computer and for how long he survived is unknown, but the skeletal remains in front of the computer and the second set of remains just inside the entrance to the Dunwich building accompanied by a box of ammunition and a box of grenades seems to fill in the missing details with horrific finality.
I've never encountered anything like that in a game. Having one, meaningless location become the setting for multiple interesting events that all occurred before you even set foot inside.
It's about the details in FO3 for me. One poignant moment struck me as I was wandering the wasteland just walking back to my place in Megaton. I came across some ruined houses and walked up to a mailbox. Inside the mailbox was a Vault-Tec rejection letter, informing the family that they were unable to admit them into any of the nearby vaults. Just to rub salt in the wound, if you check by the door, you notice a few packed suitcases.