I regret missing both the Danny Burstein and Yiddish productions. (I was rather predisposed to not love the actual production, but I wanted to see Danny Burstein.)
Plenty of unmemorable Fiddlers, but I'll never forget seeing Jan Peerce in a summer Musicarnival / Kenley Players production in northeastern Ohio around 1971. I went, not expecting much except to enjoy seeing him do something else after he'd sung a couple of concert operas with us in Cleveland, but I was stunned at his performance, so full of humanity, and how affective and heartbreaking I found, for the first time, the "Little Chavala" scene, thanks to his singing.