This is a very important question. Drawing Maps, especially for testing purposes depends on dumping things from your brain to paper as they come to you. The problem with Map creation software is Mouse and Keyboard, take time to draw a circle(Or at best position a circle), and write things inside the circle. Brain doesn't work in get-idea->hibernate-until-recorded->proceed mode. Our brains pretty much reach an idea, and then proceed towards the other. For that you need a quickly interacting tool. Pen/Paper, Whitboard/Marker is the best tool at this time for that kind of a purpose.
Another advantage of White board is the size. Many software teams gather create a map on a big white board, take a photograph and mail the team.
Also stuff like using Pen/Paper has separate advantages. Like putting in quick note points, or a diagram etc.
A map editor is on my todo list though. The goal is to make something where I can do exactly what I do now (type things down, little to no mousing involved, minimize time spent on the circles/organization/whatever) and shuffle the data around when it becomes more convenient. Diagrams and drawings will still be a pain though. Maybe I'll get a Cintiq or something :-)