I'm a boy, but I definitely liked Barbie dolls when I was really little (like 3), and I had a couple of my own. I used to play Barbies with my best friend next door (a girl). In a way, it was kind of fun when my little sister was old enough to play Barbies, because she almost always wanted to play with me. I was about 12 by then, but I still enjoyed it.
When it comes to childhood toys, though, my real thing was die-cast cars. I had a huge collection of these, though most of them are long since lost (or sold). The toy cars kind of went with one of my earlier obsessions (cars), and when I became obsessed with roads/highways later, I expanded on that by buying plastic roads for my toy cars.
Personally, I preferred Matchbox, as I thought they had a better selection, though the majority of my collection were Hot Wheels.