There has been some noise lately about Fluent NHibernte. This gives you a fluent interface to configure NHibernate mapping. I don't really see the point, frankly. Fluent NHibernate, at least in its current stage, requires a mapping class per entity. At this point, I might as well use the XML again. In general, anything that requires me to touch two places to make one change is suspect. That is part of the reason that I like ActiveRecord, the change is highly localized.