For instance, I like:
Colter Wall, The Dead South, and Flogging Molly (although I've been drifting away from Flogging)
"In Hell I'll Be In Good Company," "Big Iron," "Boots," "Seven Deadly Sins," "Tobacco Island," "Toronto Man," and many others.
Mostly Bluegrass, Celtic Punk, Irish music, and old, folk country (Mind you, not the modern, Josh Turner kind of country--I don't like that--but the old folk kind of country. Check out Colter Wall to see what I mean, or Imaginary Applachia for a more Bluegrassy approach.) But like I said about Flogging, I've been drifting away from Celtic Punk and more towards bluegrass and Colter Wall kind of music. I also occasionally listen to Streetlight Manifesto, Steve n' Seagulls, Big Real Fish, or sometimes blues. But, if given the chance, I would go with the options listed above.
Let me know what your favorites are. Also, if you're any sort of a Bluegrass person, some more Bluegrass bands or performers.