March Entry: Dwarf Fortress
I'm not a cartographer, but I do enjoy a good map. I'm a Dwarf Fortress player and decided to fiddle around with it's sophisticated map tools to see what I could come up with. Attached is the result (getting more than one river in a square: trivial; getting one river in every square: damn difficult! I actually cheated, I had to add three small rivers over 5 or 6 squares to finish off, but I was more concerned with getting the provided rivers matched up as close as I could--edit: likely they're hard to see due to the dense forested areas, but I assure you that they are there).
You are free to disqualify this entry on the grounds that it was generated by a program, but it's still impressive. Included are two 3D renders of the heightmap as well. :) Nothing fancy, just a cheap viewer I found that was easily compatible to the bitmaps that Dwarf Fortress exported (though I do scale them for size and convert to png before attempting to use, anything over ~1024x1024 is slow, and anything over twice that crashes the program).
Submission is cartography.png, the renders are central.png and western.png
Central shows off the central lake and eastern mountains.
Western gives a view of the western mountains.
The mountains look odd, but Dwarf Fortress sorta has 3.5 notions about height: underwater, flat grassland, mountainous, and peaks. Peaks aren't that much higher than mountainous, but mountainous is significantly higher than grassland, and oceans/lakes drop off dramatically. Rivers are also significanly eroded into the surrounding areas (limit of the 256 levels worth of height the game stores?).
Here's a render of a completely game generated map for comparison.