Mark
I'm not an expert on architecture, so my opinoin may differ from the group's, but here's a few that I think are worthwhile. Unfortunately, places like the Grange are no longer a cheap greenfee.
The Castle, Rathfarnham, Dublin
Baltinglas, Baltinglas, Co Wicklow.
Arklow Golf Links, Arklow, Co Wicklow.
Ardee Golf Club, Co Louth
Coollattin Golf Club, Co Wicklow
Courtown GC, Co Wicklow
Delgany GC, Co Wicklow
The Hermitage, Co Dublin
The Curragh, Co Kildare
The Heath, Co Laois
Eskerhills, Co Offally
Mullingar GC, Co Westmeath
Tramore GC, Co Waterford
Cork GC, Co Cork
Connemara, Co Galway
Carne, Co Mayo
Enniscrone, Co Sligo
Strandhill, Co Sligo
Donegal, Co Donegal
plus all the ones Philip mentioned. Some of those listed I haven't played in a long time. I would be happy to play any of them.