In Hiroshima I stayed at the Guest House Carpe Hiroshima Koi which was a nice place to stay for a few days.
The owner was very helpful and a big baseball fan, his Hiroshima team was in a playoff promotion game the night I arrived and he was excited and hopeful. Unfortunatley they did not win.
The transport links to the two main sights in Hiroshima are great with the hostels location being right next to Nishi-Hiroshima Station which is half way between the A-Bomb Dome and Miyajima Island.
I would recommend this hostel to anyone visiting Hiroshima, I paid around £10 a night which is a very fair price.