I usually use my own format in a text file and create a parser for it, but lately iv'e gone with INI files and they work fairly well and are structured well enough.

Although it would be nice if I could....

[PLAYER]
position=0, 0, 0

You know like have comma delimited values in a single keyvalue, although I could read it in as a string and parse it myself, I might aswell just not use INI at all in that case lol.