I've been playing in a traditional Irish folk group for a little over a year now. We did probably a dozen shows last March and three on the 17th! For more traditional stuff, you gotta stick with Clancy Brothers and the Dubliners. You'll have an easier time learning those as well if your more of a folk band.
We do throw in a couple Dropkick Murphys, Pogues and Young Dubliners when the crowd is a bit younger.
BTW, if you work up an "all Irish" set there are about 2.3 million festivals and pubs you can get fairly easy work from