Sean O'Riada is an interesting Irish voice. He was primarily involved in the resurgence of Irish traditional music; after his premature death his band became The Chieftains. If you want to hear what they sounded like before superstardom and commercial excess got their claws into them, try the album "O'Riada sa Gaiety" on the Claddagh label.
O'Riada also produced some film music (notably for the film Mise Eire, about the 1916 Easter Rising) and a little formal concert music, of which I have heard his work for string orchestra Hercules, Dux Ferrariae. It's quite astringent when compared with his music in a more populist vein, but definitely worth hearing at least once. It indicates that, although stuck at the end of the world (which Ireland, culturally speaking, certainly was in the 1960s), he was unusually cosmopolitan in his outlook for an Irishman of his time.