While I understand the difference between a professional nanny and a "babysitter"
@EricEng I do feel it's a bit unfair to describe them as someone "who plops kids in front of the TV all day and feeds them junkfood". I'm sure those type of nannies exist, but I doubt many parents would employ a nanny like that for a longer period of time!
I had a nanny growing up and she was lovely. She took care of me from 6 weeks after my birth until I started school. I have lots of fond memories of her. She was a SAHM whose children were grown up. She read books with me, we went on walks, we went grocery shopping, we cooked, in short, I did everything a SAHM would do with her child, except I was not her birth child. I feel very lucky to have her in my life and we've always stayed in touch. I really appreciate that my mother was never jealous of another woman mothering me. I'm also glad my parents didn't send me to daycare (although my town didn't even have a daycare when I was a young kid, everyone's mothers stayed at home except for mine) because I don't think kids in daycare have the same continuity, they don't form such strong bonds with their teachers.
My friend also works as a nanny for a family. She has a teaching degree so she knows a bit about childhood development, but she's certainly not like a private preschool teacher. She's great fun though and takes the kids on frequent visits to the library and the petting zoo, they do lots of crafts. I don't have kids but I'd hire her in a heartbeat.