Aw hell, I'll mention 3 more anyway:

W.O. Mitchell
Ernest Hemingway
Ian Rankan

Sure, and Roddy Doyle too, though The Commitments is still the only movie that surpasses the book I've ever seen. The Barrytown Trilogy is hilarious. They'd better get busy and make "The Van" into a flick before Colm Meaney gets too old.