I know a bit about hotels in Ireland, so here's a few suggestions:
Dublin - the Clarence & the Morgan penthouses have the wow factor, but at a price. The Dylan is very very nice
Galway - the G - very swish, but you'd want to have a junior suite for the wow
Kerry - the Ross and Killarney Park hotels in Killarney and the Park in Kenmare are pretty amazing
Newcastle, Co Down - the suites at the Slieve Donard are fab.. v fancy bathrooms & the spa is amazing.. good value too as it's in pounds
Belfast - the Merchant - fab, but can be hard to get rooms at times..
Kildare - the suites in the old house at Carton House are very impressive..
I know you're looking for Ireland, but Gleneagles in Scotland is pretty amazing, and it's not too expensive now with exchange rates.. amazing setting too...
As always, personal taste comes into it too.. feel free to pm me if I can help more!