I loved barbies when I was little. I can't remember from what age though.
I don't see any harm in your DD having barbie or the dream house now.
I know there's a stack of philosophical and ethical arguments against barbie (I should know, I wrote a sociology paper about it at uni!) but at 2 years old, your DD probably just wants to play with the pretty doll - and I don't think there's anything wrong with that!