These are all good recommendations and there are other books that can be helpful for more specific interests, like any of the books about the WASP, or Women Air Service Pilots, which do not appear to be available as ebooks at this time.
I just picked up
1001 Things Everyone Should Know About WWII from the library via Overdrive, but it's available for kindle as well to buy.
http://www.amazon.com/1001-Things-Ev.../dp/0767906853
I'm not sure how good a resource it will be, but will update you after I get into it tonight.