Should the US have dropped the atomic bomb in 1945?
I know I'm a little late posting on this topic (The Hick likes to read several opinions before posting his own.), but here's my take on it.
It was the perfect time to have used the Bomb for the first time. It may have saved civilization.

No one had any idea what an atom bomb could do in 1945. As far as anyone could tell, it just made a bigger crater than a conventional bomb.
If the Bomb hadn't dropped on Hiroshima, we would have gone on thinking that way. We would not have developed the fear of atomic weapons which led to standoffs by the superpowers, rather than WW3.
If we didn't have the example of Hiroshima back in 1963, how do you think the Cubam Missile Crisis would have ended? Would Russia have backed off, or would the two powers have lobbed missiles at each other?

In 1945, the war was over except for the details. There was no need to use more than 2 Bombs, and no chance of anyone firing any back. The examples of Hiroshima and Nagasaki have preserved the world for over half a century.
Cold comfort to the Japanese, but if anyone can say that their sacrifice saved humanity, it's them.