Here's what a "realistic" map looks like in vanilla Minecraft:
It looks like Civilisation II with the UI turned off.
Note that this isn't a tool for playing Minecraft. Chunky takes map files and "renders" them, which means crunching the map and giving the blocks a more natural appearance. It can take hours to process a single image like this, and it can only handle vanilla Minecraft terrain blocks (no players, mobs, etc), so it's mostly just a tool for making very pretty wallpaper.