Holly got a dress-up box for Christmas, and it has gotten the most use of any present by far. The girls play with, in, and around the dress-up box pretty much daily.
Josie loves her a pair of fairy wings.
This is Holly's favorite item, which is a skirt that I picked up from the thrift store. She would probably wear it all the time, in the house and out, if I let her. Pair this with a fancy purse, and you have this little girl's heaven.
Dress-up is pretty much a constant activity in our house. I honestly don't know why I even bother getting the two of them dressed in "real clothes" every morning.
Another favorite is to take all of the clothes out of the box and then use the box as a bathtub, car, airplane...anything. And don't forget "swimming" in the pile of clothes on the floor! Some days I can hardly stand the mess this creates, but they have so much fun with it, who cares?