There are several kinds of campaign worlds available for the DM. First is the fully-fleshed out world (Forgotten Realms, Greyhawk, Eberron, etc) that is chock full of history, culture, and campaign ideas. The drawback is that DMs sometimes find themselves re-writing campaigns to accommodate new products and novels. For every campaign idea, there is a potential metaplot roadblock that will be thrown up later. Another drawback is the drain on the wallet from the expensive (but beautiful) sourcebooks that keep coming out.
Then there's something like Cartography, volume 1. This little pdf is $4.95 and has 4 maps (continental, regional, local, and urban) of a land mass called "Roen." The maps are for a campaign setting: The Last Dominion: Echoes of Glory. There is more to stimulate the imagination here than can be found in many of the multi-book, mega-publisher campaign settings.
The artwork/cartography is simply beautiful--on par with the major settings today. Printed out at maximum dpi, the maps look great, and the detail is excellent. The continental-scale map covers a huge amount of territory, and only the major cities are indicated. The names for countries and regions give a sense of where civilization begins and ends. The map of Roen has some intriguing possiblities: what are the Fallen Kingdoms? How did they fall? What secrets lie in their ruins? Glancing at the map reveals a nice blend of civilization and wilderness, as well as a good mix of terrain and climate types.
The regional map, "East Middea", gives a strong sense of how populated the region is; that entire region is very well detailed. East Middea is the only region detailed here; the rest of the continent is left to the DM and players and their imagination. A party could spend an entire campaign in this region alone, and the map is a great example of how the rest of the world could be fleshed out.
Then find a small lake on the East Middea map: Adderhold. That lake and its surroundings are further detailed on the third map, which differs from the others in that it is 3-D (and very well done, I might add). One gets a sense of every contour of the land.
The final map is a city map; these don't normally catch my eye, but it was also a great blend of detail and room for imagination. <br><br>
<b>LIKED</b>: The beautiful artwork/cartography! Only the bare minimum of examples on how to flesh out the world. This fills a great middle ground between a simple world map and a fully-detailed setting. <br><br><b>DISLIKED</b>: Nothing!<br><br><b>QUALITY</b>: Excellent<br><br><b>VALUE</b>: Very Satisfied<br>