I have never been much of a fan of Barbie dolls. Miss.-5yr-old also shows little interest in them. But in the last couple years we have built our Calico Critter collection up in place of the typical Barbie. These figures were around when I was small (under the name Sylvanian Families) and I still love them.
They are not at every store, but you can find a plethora of characters and accessories online, at toysRus, Barnes and Noble or Specialty dealers.
I love how innocent the characters are, that they are purchased in family clusters, and the endless possibilities of play with all the themed accessories.
To enhance Miss-5yr-old's play I made her a play mat. It was made from 2 yards of canvas. I hemmed the edges and got out my acrylic paints (the green did take a couple extra bottles). I wanted Miss.-5yr-old to be able to make several play scenarios with the scenery (gardening, hopscotch, picnic, swim or fish in pond, tube down the river, pick flower, go camping, etc.)
Mr.-3yr-old plays with his sister. I don't think he would participate the same if they were playing Barbies. Now they have somewhat of a cost. Some sets seem like you get more for your money than others. They often go on sale so watch for the deals.