Dwarf Fortress seems to do a really good job at creating plausible fantasy maps. Mountains are created as blobs near the edges of a continent, without 90° directional changes. Rivers flow from mountain ranges to basins. Vegetation is dependent on the overall climate of a region. Settlements are created according to race-specific traits (dwarfs in the mountains, humans at rivers, elves in forests). Volcanoes are an exception, as the seem to be randomly dotted all over the map.

All in all, Zach, the Dwarf Fortress creator seems to have put some thought into the (game-wise) mundane task of world-creation.