We’ve dealt with the questions of where to buy a very big wall-sized world map and which world atlas is best, but these subjects came up on Ask MetaFilter recently, and you might find some of the answers useful: the world map question got some answers not mentioned here; and, in the best atlas thread, the majority view was that the Times Atlas of the World was by far the best. Note, though, that an 11th edition of the Times atlas is coming out next month.