While I maintain that Darlene's World of Greyhawk maps are still, after nearly 30 years, the most beautiful maps ever produced for any fantasy roleplaying game, there are others that equal (or even surpass) it when it comes to evoking the sense of wonder I seek in most RPGs. A good example is William Church's map of Prax from the second edition of RuneQuest.
For me, this map will always represent my vision of RQ, a game I rarely played back in the day and whose direction over the years has made it less and less like anything I'd want to play. At the time this map was published (1979), though, RuneQuest was just a very imaginative fantasy game rather a mere vehicle for Greg Stafford's theo-sociological flights of fancy. With its Bronze Age society and peculiar takes on many of the standard tropes of fantasy, the game nicely distinguished itself from Dungeons & Dragons without resorting to the "D&D but better" tack that most other fantasy RPGs employed in their attempts to acquire mindspace in an increasingly crowded market. RuneQuest was very much its own thing, unique and confident, as I think the map shows. Every time I see it, I wish I had played RQ more often and even briefly consider giving it a whirl again, freed from the setting accretions dragged it down and sucked much of the joy out of it.
Maybe I will someday.