The Cliffs of Moher is a "must see".  We went on a drizzly day, but it was still spectacular!

Cliffs, pubs, and peat fires...are the three main memories I have of Ireland. We rented a stone cottage in a small little fishing village close to Galway. There were three more pubs a stone's throw from the cottage:-)

We went in April...a little cool, but entirely pleasant!