Currently I'm planning a custom adventure "Story" map. Can't say the plot of course, but I try to draw out the map to plan out my landscape for the game.

Last time I tried to go with a map and make stuff from the top of my head, but that was a total fail. I found MyPaint and started some neat maps to make my Custom Story. Not only that, but it was a lot easier to label things that the player where to go.
P.S: If you like, you may ask for tips. I'm not really an expert on this subject, but there will be people here who might help the new map makers too.