C.K.
There are a couple right in the heart of Lansdowne--one that specializes in kids stuff (although they may be phasing out the clothes, I'm not sure) and right next to it is the Delaware County Memorial Hospital thrift shop. It's actually pretty decent.
Otherwise, check the further suburbs--I know the Goodwill out in Berwyn is far away, but because of the area it's in they have REALLY nice stuff sometimes. :)