Monty, 

Good question. I have to admit that I am a penny pincher and have not yet stayed at an Irish castle. I was going to do so this spring but the volcano foiled my plans. I may yet do so later this year. 

I suppose staying in a castle is like kissing the Blarney stone. Everyone does it so you must too. But since you say you don't really have that much desire to stay in a castle, perhaps the cost is not justified for you. There are some "budget" castles in Ireland. You might take a look at my Castle page for listings. One of those "budget castles" is Smarmore Castle, which offers my readers a discount (see Hot Offers section of the forum). Smarmore is one I hope to stay at and check out this year.
 
If price was not important I would want to stay at Ashford or Dromoland. I recently stayed at the villas at Waterford Castle. Although I would not recommend the self-catering villas I did think the castle was very nice and the setting (on a private island in the river) was lovely. 

Just remember that all the castles listed on my Castle Hotel page are not necessarily places I would recommend. It is merely a listing. If you are interested in a specific one just ask me.

Michele