I'm right with Jaxilon. Just... Not as far along the artistic road. But the viewpoints are similar. A map for an RPG or fantasy world or other piece of fiction should help to give definitive shape and dynamic to the mind of the player/reader. It should draw them in, make them wonder, and give them a solid foundation. So it should be an accurate representation, and therefore not so thrown to the wind as to shirk accuracy altogether (like the London Underground map).

If I'm viewing a fictitious map, I want to know a number of things. What's the location of this? How far is it from that? Which direction to here? What else geographically is around it? What's the terrain like, the climate, the fauna and flora? Most of these can be inferred or specifically shown on an artistic map. These things, for me, compile together to give my mind a clearer and hopefully more accurate image while I follow a character around on the page (or in the game). For me, that is the intention. After that, the more aesthetically pleasing the map is, the more fun it is to hover over it and study it. And I love spending that time with a great map. It can be as good as the story itself. It brings the world to life.

In these regards, I want some noticeable degree of realism. I want the designer/cartographer to take interest and show care with the details. But at the end of the day, it's still a work of art, and it still has a story to tell.