D-Day was an operation done as much for political reasons (letting the Allies be seen as liberators instead of fortress-sitters) as for military considerations. It was, I believe, done through a genuine wish to help the Russians in the East. It was necessary from the political sense, and perhaps also from the military perspective as it divided the German forces, though it was less necessary from this point of view. Losses were not as great as feared, and definitely yes, I agree that losses on many Pacific islands were greater perhaps not numerically but at least in terms of proportion of invasion waves. Betio comes to mind as a good example.

Just my two cents. Gelatinous Cube, Oppenheimer actually said 'I am become Death, shatterer of worlds.' His words... Just so your quote is more accurate. I like that quote, incidentally :)