What do I know about the geography of this world? Well, basically, it's the same as that of Earth. Why? Because it is Earth. It is Earth a few thousand years into the future and after a terrible nuclear war.
Therefore, the map is the same as that of today's Earth. Continental drift doesn't occur on a time scale of a few millenia - it takes much more than that. As much as I would like to push the continents a little bit, I don't think I will. Unless I somehow come up with a semi-plausible explanation, such as humans somehow managing to speed up the continental drift either permanently or temporarily.
Something I do find more plausible, however, is raising or lowering the sealevel. I'm really not sure how much is plausible, though, or how that would affect the rest of the world, so I'm not saying anything definite about that, yet.
Places of high militaristic value around our time would likely not be inhabitable. Thus, I imagine much of the American east coast will have been bombed to pieces. Same thing with other places that are densely populated in our time.
In our world, Mesopotamia and the countries around the mediterranean are considered the "cradle of civilisation". I'm not sure whether this would be because they were just plain lucky, or if it was because of the geographical advantages they had. I will look into it and then decide what place in my new world will be most advantegeous to start new civilisations.