Any particular areas of interest? There are some similar if a bit more focused threads here already that might be worth examining. Does your interest lie in naval, air, ground, or some mxi? Europe or the Pacific? Specific battles or camapigns?
There are so many books to recommend. You'll never be satisfied. I echo lwd when he says you need to be more specific in your interest. Check the What Are You Reading thread for suggestions.
One way is to check out wiki for the various campaigns. You will get some info there and often a decent list of references. If you find a campaign of particular interest you'll likely get more responses if you as specifically for that. Wiki's pretty decent in any case for a general over view. You might also want to visit hyperwar. They have a lot of primary documents including some books available (digitized some in html). The US Army Green books are decent as well and they are all on line and available for free on at least some of the sites.
I came across this book called "The Pacific Crucible" written by Ian W. Toll. That was written in the pacific theater. I'm looking for a similar book written in the European theater.