New York would be nice. Moscow would be cool. But then it would maybe be too much like Metro 2033 (great book btw!). Berlin and some post apocalyptic fourth reich thing with nazi super mutants thinking they're the master race? Or crazy humans having ghoul/mutant concentration camps... I'm currently playing F3 for the first time... But it seems it has the curse of the first two (New Vegas didn't have this so much) in that you sort of have to wear power armor and s*** like that to complete it. I prefer it a bit lo-fi. Ammunition should be way more uncommon and expensive. And you should be able to complete the game in a dirty prewar suit and a .32 gun! ;-) Also they should make cars available!