James Gelvin's The Israeli-Palestine Conflict: One Hundred Years of War has gone over pretty well in my classes -- by which I mean, both the pro-Israel and pro-Palestinian students have both been mildly offended by various parts, which I figure is about as evenhanded as it gets!

Seriously, though, from my perspective as an instructor and historian, he does a good job of laying out the basic issues on both sides, and pointing out where the disconnects are (one of the problems with trying to find a solution being that events that were very significant to one side are sometimes not even a blip on the other's radar screen, so quite often they're not working with the same points of reference). It's very hard to find something completely unbiased, but this is about as close as I figure it's possible to be while having a background as a specialist on the Middle East.