Was the nuclear bombing of Japan WW2 the wrong or right thing to do?

[ford man xf]

I have had the discussion with people before regarding the nuclear bombing of Hiroshima and Negasaki and often a lot of people say it was the wrong thing to do and it should not have been done it was a great injustice etc. etc. but the way I look at it an invasion would have cost more lives on both sides, dragged the war on for longer and more conventional bombs would have been dropped anyway. People say it was a waste of lives but surely most of those people supported the Japanese war efforts anyway...

What are peoples views?