I also forgot to mention for girls American Girl Dolls are going to be super collectible.
My daughter has an American Girl Doll that we purchased for her prior to Mattel purchasing them. She has played with the doll but not a whole lot and the doll is in mint condition. Lately she has been reading the books that go along with the books.
A few years ago, American Girl Doll came out with a line of smaller scale display dolls called "Girls of many lands" or something like that. It was a huge bomb and American Girl cancelled the line. The dolls sold for around $50-$60 but when they discontinued the line they were selling them for $30 and eventually dropping to around $15 or so to get rid of them. I bought the entire set and gave my daughter one each Christmas, Easter, Birthday. I now see the doll from Ireland is selling for $500 on EBAY MIB already!!! Her's is out of the box and on display but we do have the original box for her to pack back in when she tires of them.
I also agree that Harry Potter will be big. I purchased a 1st edition Bloomsbury of the Philosopher's Stone that had a 500 print run. I paid a lot for it but this was years ago before Harry Potter even became really well known. I haven't checked around to see how much that is worth today.
"The farther we go, the more the ultimate explanation recedes from us, and all we have left is faith."