I have to say that when I went to the Peace Park and the Museum, I was really taken aback. I cried through most of it. It hit me just as hard as the Holocaust museum in DC did. But I seemed to be the only person that really was upset there. There were a lot of Japanese people that were laughing and just strolling through. People that were at least mid-20's early 30's. The older people were the only people there besides me that seemed to be teary. But it definitely somewhere I would suggest visiting.

Having visited both the Hiroshima & Nagasaki atomic museums, I find Nagasaki to be the more moving of the two.  I agree with jstorm; you cannot walk through dry-eyed, but too many people do not seem to have an appropriate spirit of reverence.  I don't look at this and think about who you might hold at fault in the war; I simply see the human suffering that resulted. I'm afraid too many young Japanese really don't understand their past.   

I'm sharing two of my favorite photos I took at Nagasaki.  The first is called, I think, "Hall of Remembrances."  The view is from an observation booth from above that is covered with names or photos of those who perished in the blast.  The hall itself seems to resemble a cathedral, but to me it evokes the rising columns of flames from the atomic blast.  I think this chamber is underground, and it points directly in the direction of ground zero.

The second photo is a temporary exhibit set up for the anniversary of the bomb, some cards made by local school children.  The one with English on it in the middle, my wife translated as "Don't war."  I can't think of any better way to say it.