If you find yourself lacking good Irish music:
Altan - perhaps the best Irish traditional band, from County Donegal. I heard a clip of their music on NPR today as bumper music between two stories. This band has been going strong for over 20 years.
Bothy Band - also quite good traditional music, and haunting vocals.
Capercallie - a bit more electronic, but still very tied with traditional songs and tunes. Another 20+ year band.
Deanta - good music out of Belfast
Patrick Street - this quartet (or trio depending which album you have) plays very skillfully, and they know how to write good tunes. Their "Music for a Found Harmonium" was used in the Napolean Dynamite soundtrack, right near the end of the movie.
U2 - what can I say? Not traditional folk, but one of the best bands ever.