We'll be arriving at Dublin airport around midday & heading to County Kerry. It will be our first night in Ireland & we would like to stay somewhere special.

Any suggestions for a suitable destination after a two to three hour drive would be appreciated.

If you willing to veer off the direct route, Kilkenny or Cashel could be a good stopover.

Otherwise you probably want to stay close to M7/N7/N21 going from Dublin to Limerick and further SW towards Killarney.
In that case, 2-3 hours will take you somewhere in the Midlands with maybe less of the obvious or better known sights.

One place could be Roscrea in No. Tipperary on N7 (the major road bypassing town, fortunately), with a fully-fledged castle to visit (not THAT big, though), and a small historic town centre rather untouched by tacky souvenir shops or "made-for-tourists" pubs. Though the craic is probably a bit more real there.
http://www.roscrea.ie/content.asp?section=453

Before you get to Limerick, you will find the twin town of Killaloe/Ballina, which is just 5km off N7. It's a pleasant small place on the Southern edge of Lough Derg. There are only few sights, though.
http://www.discoverkillaloe.com/

I would recommend going west from the airport to the Edenderry turnoff .. R.402 to Tullamore ... south on N52 to Birr, County Offaly... and if not too tired take the loop to Shannon Harbour and Banagher and then to Birr if nothing suited.
Going still further the Lough Derg area is a good option.
If by "something special"you are thinking of accommodation I'd recommend Georgina Campbell's Guide...www.ireland-guide.com.

(AND ...Because it's not well publicized I always mention to folk heading to Kerry that there is an INTERNATIONAL(!) airport near Killarney.
Ryanair fly from Dublin 3 times a day -- one flight 14.05 arriving 14.50 ... present cost 20 Euro inclusive of taxes.)