Castle Kilkenny is amazing. A bit more Victorian than my medieval tastes run, but overall just beautiful. Only the most jaded would fail to be impressed by the medieval basement corridor, the splendor of the restored library, or the familial decadence of the Portrait Room (there must be more than 50 portraits in there, starting from the 1600s). The €5 audio tour was well worth it, and I got to keep the little MP3 player as a souvenir. Sad that the interior allows no photos, but I understand why and don't begrudge them that.
The builders understood design and layout: all of the bedrooms have a view of the Rose Garden. Outside, the Rose Garden is a small but lovely Celtic cross design with a fountain at the center, nicely shaded and very pleasant to just sit in and enjoy the scent of roses and the sound of the fountain. Overall I spent more than two hours enjoying the castle and its grounds. If I were a resident, I would certainly love to spend much more than that with my dog in Castle Park.