Roy Osherove writes about typed DataSets and appropriate use. I would take it even a bit further.
If you look at them closely, DataSets are nothing more than a relational programming model for the XML Infoset. The DOM is a hierarchical programming model for the Infoset. XML Serialization is an object-typed programming model for the Infoset. Typed DataSets is a schema-bound programming model for Infoset and with that its really a relational programming model to PSVI. Still, it's a programming model for Infoset and I would argue that sharing programming models (or forcing programming models upon others) across boundaries isn't a good thing. Sharing serialized Infosets (one way to do so happens to be called "XML 1.0") is a Good Thing.
Update: Read the comments.