I think this is my first PCKF post ever (i'm more of a keenmodding.org guy) but i logged in to pass comment, I used to listen to these on a cassette a lot... I used to sing 'an bhfaca tú mo ShéamuisÃn ' and the other two a lot in school, great simple little tunes! I was (even in my single-digit years) a little cynical of their modern instrumentation, but they're not bad really!
have you ever listened to the Dubliners? or Planxty? strongly recommended!
http://www.youtube.com/watch?v=dm69TUoSCkw
more rough and ready than n Casaidigh, but a more authentic sound too!!!
http://www.youtube.com/watch?v=JyP407UnUWw
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on a slight self-promotional tangent (i hope this isnt forbidden), have you ever played 'Bunny Basher 2'?
http://maguidhir.com/benvolio/ and click 'Bunny Basher 2' on the right hand side!