YAML, for the simple reason that it makes for very readable configuration files compared to XML.
XML:
Bob
Abooey
adv
| 555-1212 |
ahunter@example1.com
babooey@example2.com
YAML:
babooey:
computer : cpu1
firstname: Bob
lastname: Abooey
cell: 555-1212
addresses:
- address: babooey@example1.com
password: xxxx
- address: babooey@example2.com
password: xxxx
The examples were taken from this page: http://www.kuro5hin.org/story/2004/10/29/14225/062
