Alasdair Fraser has got to be my all-time favorite Celtic-style fiddler. (And Natalie Haas is my favorite Celtic-style cellist… big shock, right? 😀 ) As far as Old-Time/Bluegrass/Canadian fiddling… wow, it’s hard to pick. I’ve heard a lot of really great players, since my family goes to fiddle competitions all the time. Matt Hartz and Calvin Vollrath sure are amazing.