A regular annual vacation out of the country. I grew up in Europe (born in 1949), by the time I was sixteen quite a few of my classmates went on vacation with their family to Italy, France, Switzerland, Austria, Hungary, Denmark - you name it.
I've always had the travel bug so that was the only thing I wished we could afford.
Being gifted - your own, nice car by the time you graduated at 18. Even the well to do rarely gave their kids brand new cars, that didn't happen until the late 60s - early 70s.
A house with all amenities, huge bathrooms and a state of the art, built-in kitchen. We owned a really nice three apartment house, but it was built in 1901, so no nice big bathrooms or cool kitchens at the time. I renovated when I inherited, years later.
Beyond that, I never really cared what other kids had, their own swimming pool or membership to the tennis club or the first color TV or whatever. Shrug.
I still think of Coca-Cola as a treat not to be over-indulged in.
I did get to travel with school (our high school teacher liked to travel with us at least twice a year - bless him:) and also when I won trips by being the best on the political debate team. My favorite was a trip to Strasbourg, France, and the surrounding countryside - best food, candy and wine ever:).