My girls love both their wooden doll house and their wood playhouse (out in the garden). The playhouse is great...it allows us to get outside and play, even in rainy Scotland.
My girls also both love dress-up stuff. They have a fairy outfit and a few other things, but not much...so we are planning to expand their dress-up collection this Christmas as their main present.
Any and all arts and crafts supplies go down well...beads to string into necklaces, collage supplies, different kinds of paints, etc.
Both of my girls also love little figurines/dolls/etc. that they can use to play in their doll house (or alternatively, that can be 'guests' in their playhouse for their tea parties).
And we have a small (plastic - sorry!) kitchen with lots of different pretend foods, plates, cups, utensils, etc. And they LOVE that...they play with that stuff all the time....
Just be careful not to buy too much! I went through all the Christmas stuff I have for the girls yesterday, and I've already gone overboard, and I thought I was being much more careful this year.
So easily done, I'm afraid...