Mary Martin. I was obsessed with my VHS recording of it as a child and watched it until it wore out. Then payed a small fortune as an adult to get another copy lol. I saw Cathy Rigby several times and while she is fantastic no one could ever compare to Mary Martin for me.
I know I'm late for posting, but FOR ME it's a toss-up between Mary Martin and Cathy Rigby. Though I have to say that after seeing Cathy play the role in person at the Dallas Music Hall in 2012, she gets my vote.