I always felt that the atomic bombing of Hiroshima and Nagasaki where terror bombings. But the USA was not filthy of terror bombing the Japanese into submission.
Nowadays terror bombing is considderd a warcrime. But in WWII it was quite common
Against an enemy like Japan, who wasn't going to surrender because of loss of territory or loss of lives, terror bombing them into submission seems the only logical alternative. Since fireboming didn't help, sending 1 lone bomber to drop a bomb that destroys a city would be a good way of forcing the surrender. However, it has to be a city or the 'terror' portion of it will be lost, and that what the Japanese government and population needed to feel. If you drop it on a military complex, the Japanese won't see it as a display of power but just a strategical attack, one of many.
The option without terror would be the invasion of Japan itself. I once made a thread about that. Since then, though i despise terror bombing, after all i've read about the planned invasion of the Japanese homeislands and how far the Americans and Japanese where planning to go i would rather see 2 cities filled with civilians(and some POWs) destroyed by nuclear bombs then that. Everybody would. The loss of life would be unmeasurable, it would have changed the face of the war in ways even 10 nuclear bombs couldn't.
Even, i would rather see them dropping biological weapons and kill the population undiscriminatly then see Operation Downfall into motion.
In the end i believe no that the bombings of Hiroshima and Nagasaki saved the people of Japan(and the USA) a lot of pain and suffering. Dropping the bombs on a mountain, forest or military target only endangers that fact.