Don't underestimate XML! It's got parsers already written out the wazoo, it's simple enough that a user of moderate abilities can figure it out and edit it (if Joe Blow can learn HTML, surely he can learn this), and if he can't, there are XML editors out the wazoo as well to help him on his way. A structure as returned from
can be just as efficient and look exactly the same as you'd expect a complex data structure as returned from a proprietary config file format.