Holly:
Dublin is okay but IMO, its the 'rural' parts that showcase the authentic Irish character.
Don't know if it has changed since the several times I've been in the early to mid 90's. But I'd recommend go west thru Mullingar and Athlone, all the way to Galway. Or, alternately, to Donegal. I thoroughly enjoyed the rural Irish mores, especially the pubs and how they welcome strangers. If I didn't fill my mouth and go spit it out, I would get drunk from the many free drinks I get in the rural pubs with a wink and some Gaelic thrown in.
-Carlton