Who is it? I love Andy M. Stewart and Archie Fisher.
Andy M. Stewart. Doesn't matter WHAT he sings, it makes me alternately tear up and wanna yell 'cause it's so good. ;-) Heh...yeah, I'm odd. I especially like the Silly Wizard songs that have him. His own CDs frequently have members of Silly Wizard, but it's not quite the same.
Manus Lunny sings on some of Andy's CDs, but I don't care for him as much.
And then there's Dougie MacLean - totally, totally different, but I like his stuff, too!
Also like Old Blind Dogs' lead singer...though their music is mostly really traditional Scottish ballads...and while traditional Irish ballads all seem to be about drinking and mourning, Scots ballads are about sneaking in girls' bedroom windows at night when her Dad isn't looking...
And the Wolfstone CDs that have Ivan Drever as the lead singer (not all do) are awesome too.
Wayyyyy more info than you wanted, right? Andy's the best, though.