Colin Hay has a nice accent, but it's not Irish. He's actually Scottish-Australian!
Here are some of my favorite artists:
Indigo Girls
Carbon Leaf
Hayseed Dixie
Pamela Morgan/Figgy Duff
Johnny Cash
The Carter Family
Justin Townes Earle
John Prine
Polecat Creek
Carolina Chocolate Drops
Sarah Lee Guthrie and Johnny Irion
Anne and Pete Sibley
Chatham County Line