I highly recommend Loreena McKennitt. She's more of a spiritualist and she takes the perspective of many different religious views. Her Celtic music is in more of her earlier works and her latest album from 2010 returns to Celtic tradition. It's titled 'The Wind That Shakes The Barley'. I haven't caught up with her yet but she's gifted for sure! Also, Blackmore's Night is good. I'm not too sure if they're Celtic but they have the sound of it. Blessed Be!