Well it all depends on how rebellious you want to be and how many people you want to get on the wrong side of because there are some excellent Irish rebel songs such as Come out you Black & Tans and The Easter Rising. I think maybe something by Cara Dillon like Garden Valley, There were Roses or Cragie Hill would be good and if you seriously want to touch a nerve there's a song by an American artist that the people of Ulster have sort of adopted and that's Broken Things.

If you are in the mood log in to you tube and search for TheGhostofCasper you should find a few good/unusual Irish folk songs on there

Slainte

cass