My turn.
I am a huge fan of Celtic and Caltic-like music and here's a list of my faves:
Celtic music and folk singers I like from ireland, Scotland, and England:
Altan (Irish)
Silly Wizard (Scottish)
Archie Fisher (Scottish singer)
Battlefield Band (Scottish)
Blazin Fiddles (Scottish fiddle group)
Cherish the Ladies (Irish)
Cheiftains (Irish)
Craobh Rua (Irish)
Danu (Irish)
Eileen Ivers (Irish fiddle)
Waterson:Carthy (english folk)
Jean Redpath (Scottish singer)
Jez Lowe and the Bad Pennies (english folk singer)
Celtic Fiddle Festival (Iriah and Canadian fiddle)
Liz Carroll and John Doyle (irish fiddle)
Lunasa (irish)
Martin Simpson (english folk singer)
Nic Jones (english folk singer)
Old Blind Dogs (scottish)
Ossian (scottish)
Solas (irish)
Teada (irish)
Tannahill Weavers (scotttish)
Canadian folk groups and folk singers I like:
April Verch (Ottawa fiddle)
Barachois (PEI group)
Barra MacNeils (Cape Breton group)
Beolach (Cape Breton group)
Cottars (obviously on this list)
Stan Rogers (canadian folk singer)
Garnet Rogers (canadian folk singer)
Great Big Sea (the best ever)
James Keelaghan (vanadian folk singer)
Joe Cormier (cape breton fiddle)
Le Vent du Nord (quebec)
La Bottine Souruente (quebec)
Natalie MacMaster (cape breton fiddle)
The Paperboys (vancouver celtic/bluegrass/spanish band)
Quagmyre (fiddle rock and step[dancing from ottawa)
What I like in the USA:
Beaosoleil (cajun)
Bela Fleck (banjo)
Bruce Molsky (bluegrass fiddle)
Crooked Still (bluegrass)
Darol Anger and the Republic of Strings (bluegrass/jazz)
Acoustic Hot Tuna (acoustic blues)
Mark O'Connor (fiddle)
Old Crow Medecine Show (string band)
Red Stick Ramblers (cajun/western wing/jazz)
Richard Shindell (american folk singer)
Kelly Joe Phelps (american folk singer)
Tim O'Brien (american folk singer)