I use AutoRealm for some maps, but for others I draw things out on a mat with the wet-erase pens. But I always wipe off the lines at the end of the day, as per the instructions for the mat. Problem is, if we're in the middle of a combat when we have to break, then it's a pain in the foxbat to have to re-draw it. And, in general, any time the players return to a location, how do you remember where everything belongs?
AutoRealm is very nice, but, unfortunately, it doesn't run on Mac. (sniff)(sniff)