I've noticed over the years that when a new version of a product is release (or close to release) I discover features of the old version that I didn't know about - and wish I had known about a long time ago!

I just found an article by Shawn Wildermuth that describes how to annotate dataset schema to alter the generated code.  This is not a new idea, the article is dated March 2003.  Well worth a read if you hate the way null values are treated - especially date fields.  Wish I had know about this in 2003 but I think it still applies to the new stuff.