I adored Fallout 3, so I'm fairly sure I will. If the PC-version is mod-friendly, then it'll be mine.
And although it'd be very interesting with a Fallout-game abroad, I do agree, it's not the best idea. A lot of the spirit of the universe stems from the nostalgia of an alternative '50's, where the atoms were mankind's future, there was a moist steak in the oven, a Nuka-Cola in the fridge and America dominated the globe. Well, before all the false dreams came crumbling down 'round our ears. It's that atmosphere that sucked me in, and it'd be difficult to recreate abroad. In the same way I don't think S.T.A.L.K.E.R would feel the same set in Harrisburg or Fukushima.
But it's a nice fantasy, though. Imagining how the rest of the world must look like. But I honestly think it's more interesting if the state of the world is largely unknown, except for perhaps some references or NPC's.