P.R.
Hi- My daughter just turned 8 and while she still plays with dolls a bit, I can definitely see her interests turning to other "older" things.
We have tried to spend more on "experience" gifts lately - tickets to things she likes or "coupons" redeemable to a day at a museum, etc (your library will have cheap passes you can get).
She is a huge reader as well and I think the best thing we have given her is a Nook (the Barnes and Noble version of the Kindle). We always bought books for her and used the library, but this is so great for her. Certainly keeps the clutter down - she takes it everywhere and doesn't have to lug a backpack of books on vacation, etc.
She has an account and when she save up her allowance she can buy a book, we give her some as "rewards" for things, and family members give her gift cards for special occasions.
I specifically bought the one that does not allow apps - this way it is only for reading.
You could preload all the books you have chosen for her to start her "library".
Hope this helps a bit - good luck!