I'm generally biased towards smaller and more rural locations and I've learned that I'm not a person who wants to create a checklist of a whole bunch of things I need to check off my "must see list." I might try to pick one, or at most two, "must sees" on any day and then just explore. We often refer things like street markets to attractions. And we're walkers. We were also meeting American relatives we'd not never met and meeting Irish relatives we'd never met. So that dictated some of our agenda.
The Irish people generally deserve their reputation for being friendly. I'd try to engage strangers in lots of situations and it was always a positive experience. I'd crack a joke and they'd crack a joke and ... Truly lovely people.
We thought Dublin was just another relatively large city and probably wouldn't spend much time there on a future trip. Killmainham Gael Tour was interesting, but pales in comparison to something like the Eastern Penitentiary in Philadelphia. I'm probably jaded but could have lived without the Book of Kells Tour, though the long library is pretty cool. If you like beer the Guinness tour is certainly worth doing. Lots of restaurant and pub options. We did a food tour our first day which was probably the highlight. Really fun. Had a really fun guide and all the folks in the tour were fun and interactive. Certainly not a bad experience, but not on my list of must return locations.
Then County Roscommon. Very rural and probably not an attraction for most tourists. This was where my wife's family ties were located and it was very special for her.
Then Dingle. Just loved Dingle. Both in terms of the marvelous scenerey and the fun town. Stayed out later in the pubs than we ever intended. Lots of dining choices.
Then we traveled to Cork where we were going to base and fly home from. We went to Kinsale. Easy bus trip from Cork. Would've liked more time there. Gorgeous. We found great pubs and restaurants in Cork. The Shanding section is very interesting. Wouldn't spend lots of time here but not a bad base with easy trips to Kinsale, Cobh, etc.
Driving was "interesting." We returned the car unharmed, but some roads are very tight and it would be very easy to take out a mirror, scratch the side of a car, drop into a ditch and damage wheels, etc. Don't try to drive in Dublin, and frankly, I'd suggest trying to not drive in urban, high traffic areas. The M roads are fine. Most N roads are pretty good. Some R roads are pretty dang narrow, especially when there is traffic. And the L roads can be an adventure, though there is generally very little traffic on them.
Much that we didn't see and we'd very much like to return. I think we'd concentrate on doing a West coast tour. Picking 3-4 locations along the West coast as bases, each for a few nights.
Ireland is a truly lovely place and the people were just terrific.