That's a nice list, but I would add:

Ross Castle, in Killarney, Aughnanure Castle in Oughterard, Galway, Carrickfergus Castle, outside Belfast, Kilkenny Castle, in Kilkenny town, Donegal Castle, in Donegal town and -- if they ever re-open it, Barryscourt Castle, Carrigtwohill, County Cork!.

These are all nicely restored castles, but each is also markedly different.  Let's NOT get me started on ruined castles, though!

THAT list would be rather substantial!

http://www.heritageireland.ie/en/south-west/rosscastle/

http://oughterard.galway-ireland.ie/aughnanure-castle.htm

http://www.carrickfergus.org/tourism/attractions/carrickfergus-castle/

http://www.kilkennycastle.ie/

http://www.heritageireland.ie/en/north-west/donegalcastle/

http://www.heritageireland.ie/en/South-West/BarryscourtCastle/