I think both a radar and a world map are good, and an outdoor overhead, but I think that an indoor overhead would ruin the entire point of dungeons. I\'ve always liked the idea of automapping features, but I\'ve got an idea about those too
I think there should be a mapping skill, the more points, the more your maps are detailed, and perhaps even more accurate, a low skill could show you offshoots to tunnels when there aren\'t any there, and such like that.