One thing that visiting Hiroshima did was put some things into perspective....
Nearly 200,000 people died as a result of the Atomic Bomb dropped by the United States on Hiroshima (excluding the victims at Nagasaki).
The September 11 death toll was 3021.
Now, while every loss of life is a tragedy, there really is just no comparison.
According to a CNN tally, 1,129 coalition troops from 15 nations have died in Iraq. (Dated 8 September 2004)
Though, this pales into comparison with: http://www.iraqbodycount.net/
A good discussion, with many valid points on this topic can be found at:
(I do realise that these topics are very complex and many issues must be taken into consideration. )