[kurtosis]

I can imagine some circumstances where the hierarchical structure of XML would be useful, but in just about every data processing job I've undertaken that involved XML my first step was to get rid of XML and convert it to something like .csv or ascii tab delimited.

[wsprague]

If you need hierarchies, use JSON, IMHO, or keys that reference between tables (the census PUMS data does this with persons nested within households, using two tables).