Hiya Maxcast,
Isn't (aren't) Clannad the group that is featured in the Kevin Cosnter movie The Postman? If so, I've been looking for their CD for sometime.
When it comes to decent Celtic music, a good place to start is Loreena McKinnett (sp). Enya is OK but she's a bit pop(ish). Also there is Dalla, Solas and Altan. My Celtic collection isn't very deep but I do enjoy these discs.
Happy hunting!