For the thousandth time, no it wasn't.
Manatee Slayer said:
-The Japanese had virtually no Navy or Airforce to speak of.
And yet they still refused to surrender and infact were training a vast number of civilians to fight any American invasion (if their own figures are to be believed, something like 28 million [http://en.wikipedia.org/wiki/Volunteer_Fighting_Corps] - and given the kamikaze, I'm fully willing to believe they would have charged US marines with spears). As such, even with Air and Sea superiority, American casualities would have been high - and even if they weren't, millions of Japanese would have been killed in the fighting; far more than where killed by the nukes themselves.
-The Americans had blockaded Japan, meaning they couldn't get any imported recources, which is nearly everything. lol
True, this includes food, so this option was causing mass starvation agmonst the Japanese population, who where still refusing to surrender. Its highly likely that had the war continued, the Japanese would have starved to dead in their millions rather than surrender. And all the time they where holding out, thousands of POWs where being used as slave labour and worked to dead, millions of Chinese were undergoing the same, and thousands of Chinese women were being used as sex slaves.
-The japanese were terrified by the thought of the Russians coming, due to the fact they had lost to them before and that they would probably take over the country and install communism.
The Russians didn't declare war on the Japanese until after the first atomic bomb was used.
-Many high ranking officials were against the attack saying it was unnesisary and that the Japanese were ready to surrender anyway.
I believe they were only willing to accept conditional surrender - the Allies refused to accept conditional surrenders from either Japan or Nazi Germany, partly due to the war crimes they had committed, partly because the Axis forced had to accept that they were defeated, as the Allies didn't want a repeat of this war, like what happened at the end of WW1.
-Winston Churchill in his book ("The World At War") said that the bombs did not play any part in the defeat of Japan.
As great a man as Churchill was, he wasn't the god of all knowledge, and certainly wasn't an expert on what was happening on the pacific front.
-The only reason people think that the bombs won the war in the Pacific is due to American Propagada.
...Ok... thats option stated as fact - I think dropping two super weapons on the Japanese made it extremely clear to them that, inspite of their 'warrior spirit' and 'devotion to die to protect the Emperor', it simply wouldn't be enough - it showed the Japanese that the US could simply wipe them out with minimum to zero casualities if the Japanese refused to accept the unconditional surrender.
Basically, the atomic bombs, though highly unpleasant, where the best way to end the war with the minimum loss of life, and I'm sick and tired of people acting like the Japanese where wronged - the Japanese who killed millions of Chinese and Pacific islanders, tortured and enslaved millions more Chinese, and thousands of POWs, and where as bad as the Nazi's; just more disorganized in their war crimes.