Sean -
When I played Ballybunion I thought the first 6 holes were pretty ordinary. However, upon further reflection, I've come to realize that #6 is a great hole with a crazy difficult approach, #2 is wonderful and gives a preview of the dunescape to come and #1 is a very cool opener, down the dunes with the graveyard on the right. From #7 on, I was mezmorized by Ballybunion and thought the remainder of the course was simply an unbroken string of greatness.
The entire setting is majestic and Ballybunion seemed the most "Irish" course I played. I regret to only have one round there. As with most great courses, it would seem the more you play the layout the more you discover and appreciate. Of the courses I played while in Ireland/N. Ireland, my top 3 were RCD, Ballybunion and Lahinch, in that order. I really enjoyed Portrush, but thought it was a bit behind those three.