Here's my two bits. I'd have to guess that Canada and Mexico are pretty much in the same boat as America. I mentioned in another post, that I invision southern BC looking a bit like the Maze, southern Ontario and Quebec having the crap blasted out of them, and Alberta probably not being too much better off.
At least for Alberta (cause I live there), I see the northern part being a little like the Soiux (spelling?), but not as frightening. Mainly a huge Old-Wayer hangout. Most of Alberta would probably be ok (what with a 3 hour drive between our two major centres). Though there are a bunch of oil rig communities which I'd guess wouldn't fair well.
As for the rest of the world, I see most of Euorpe being a little worse off then the West. There are more closely knit centres there, and I'd imagine than France and the UK (in particular) taking a heavy beating. I actually see Russia being a little better off (physically) than America. I seem to think that since the fall of the Soviet Union, most of this area would have fallen off of the immediate radar.
Korea, China, and Japan probably wouldn't even exist. The mass population, and the modern day trend of fearing China and parts of Korea would likely land both on alot of countries' hit lists. I also see moat of the Third World having survived the bomb, but probably not the fallout and radiation.
All that said, I do think that alot of countries just started blasting out of principle, so Russia and parts of the Third World may not have fared as well. Also, Europe probably didn't have to deal much with the "Enemy Within" (bombs flying from within Europe), so I may have faired a little better, and thus be around equal level as North America.