I would like to recommend two books to you all.
The first I am sure many of you will have heard about and will probably already own, but just in case you haven't, 'D-Day' by Antony Beevor is a superb account of D-day and the subsequent battle for Normandy. I found it to be very informative and un-biased, going places where many books before had not gone, (i.e. the real reason Montgomery failed to take Caen, the battle the Americans faced in the 'real' bocage fighting), and covering the whole breadth of the battle from both allied and Axis perspectives.
I would also like to recommend 'World War II. The Definitive Visual Guide' (Editorial consultant Richard Holmes, DK books). Now I would normally never recommend a 'general' book about WW2, preferring instead the books written about specific battles in greater depth. However, I found this book to be well researched, and an excellent resource for military collectors, having many 'obscure' items pictured and documented. It is not on the scale of 'Military Collectables' but is, none the less, a very good book.