Pragmatic ADO.NET...
I by a lot of books. Not to read from cover to cover, more to skim through, and then use as a reference. Once in a while I read a book from cover to cover, especially if I am enjoying a luxuous vacation in our house in Italy. Writing from my vacation address (and it really has been a while that I posted something here) I would like to point you to a book I just finished: Pragmatic ADO.NET, by Shawn Wildermuth. Great introduction to ADO.NET with clear examples and not to thick!! I hate those 2 Kg Wrox books with elaborate, not to the point, example code. This books gives you a flying start.
Also have a look at the writers site at http://www.adoguy.com