I am born and bred Déise, would move back in the morning if my wife would let me!!! As a proud 'Blaa' (you will get to know what that means when you move!) I think Waterford is a good place to live - it is not too big, not too small (around 45,000 people) with plenty to keep you busy there. It is getting better all the time, with infra structure improving (by pass at the Dunmore Road, although I think it's still busy bnut noting like Dublin / Cork), the new bridge over the river hopefull starting soon (this should easy access from Kilkenny / north of the river) and improvements to the airport on the cards (a fine airport, underused IMHO but that may change).
Deisce - have you looked at Genzyme on the industrial estate there? I think they have plans to expand further, just a thought....