Here's a town map I've been working on and off for the last week or so. This town was built over the ruins of a much older settlement. The outer and inner walls have either fallen to decay, or the stonework has been appropriated for other uses (ie buildings, bridges, property walls, etc). Perhaps the outer walls were never finished in stone and the original wooden walls have rotted away with time. I was also thinking that the little pond at the top of the map was originally man made and originally had some tactical significance hence the tower and walls (perhaps the river was wider in the town's past as well).
The various houses I drew by hand and scanned into the computer and manipulated with Photoshop. My initial inspiration to do this map came from pyrandon's excellent tutorial: A medieval town map tutorial in Photoshop. As I digest the info in this tutorial, I'm sure I will be tweaking my own map as I try out new things.