Fallout: New Vegas is arguably one of my favorite iterations of the Fallout franchise. I love playing every new version as it comes out, but I still stand by that desert-y wasteland for now. As it turns out, Fallout: New Vegas could have been very different from the game we know and love. It was originally called Fallout: Sin City, which quickly changed to Fallout: Vegas, then finally Fallout: New Vegas.
The title isn't the only thing that was drastically different in the early days of New Vegas. Apparently, Obsidian had plans to make Fallout even more customizable than it already was. The player was originally going to have the option to choose between playing as a human, ghoul, or super mutant. That would have undeniably altered the way the game, especially considering the hatred most of the human NPCs have for ghouls.
However, publisher Bethesda struck the idea down fairly quickly. They told Obsidian developers that the process would have been far too lengthy and complicated to match weapons and armor to three different character models. Whether they were right or wrong, it's definitely interesting to know that a completely different game could have existed.
The original story pitch from Obsidian to Bethesda was actually only about three pages long. The developer had such a great rapport with the publisher when bringing up Fallout: New Vegas that nothing longer was really needed. Obsidian said they were going to locate the game in Vegas and that it would have a Goodfellas kind of feel to it. The rest is history.