I'm wondering if there's a map format that works particularly well for creating levels when you can't use a standard map/level editor?
To narrow the question down, I'm thinking specifically of 2-D tilemaps. Tiled's features look great, and I like that it is a text-based format. But even if you hand-write a Tiled map, I think the editor provides a lot of added features that would make the hand-written map fairly useless. For instance, if you're using a physics system to handle collisions, it looks like Tiled can trace your individual tiles and create individual large polygons for walls and such.
Are there any mainstream formats that we can work with? If not, what do people find works well? I'd like something a *bit* more complex than just square/rectangular rooms with doors between them--at least corridors with turns would be nice.