I spent some time in Dublin this past April and ended up staying at the Globetrotters Youth Hostel. It was very clean and the breakfast was quite substantial. The owner runs the adjacent bed and breakfast which shares a dining room with the hostel...I think that was the reason for the big hot breakfast. Overall, the rooms were clean and the location was great. Here's a link:

http://www.globetrottersdublin.com/

Hope you enjoy your trip!