If you are a bit of a maniac (like me), you can always use Blender. It's 3D software, but if you put the camera "above" the scene and render it in orthographic mode, you can make 2D graphics with it. This is how I made, for instance, this little outpost map for a game of Star Trek Adventures I ran once (attached).
And hey, if you wanna go absolutely bonkers, you can already take the step to make a full 3D interior! (Though admittedly not even I have been maniacal enough to do that, heh)