You've inspired me for a post idea on something slightly related, yet different too!
I love beautiful scents, though perfume often sets me off on a volley of sneezing! Essential oils are ideal for me. I think ylang ylang is my favourite - apparently it's one of the components of Chanel No 5, which I really love.
I can only think of a few scents that evoke childhood memories, mainly because the ones I loved as a child, I also took with me to adulthood. One unpleasant one is carbolic soap, which always reminds me of the primary school toilets and hospitals. Luckily that's one I don't often get a whiff of these days!
A couple of scents I love and that evoke childhood memories are freshly cut grass and May blossom. The freshly-cut grass reminds me of sitting on the grass at school sports days, and the May blossom reminds me of when I was about six or seven, and I used to walk past hedges full of May blossom, which was just about at the height level of my nose at that time!