Hi, M..
I second the Mandie series by Leppard. However, the plots and writing grow weak as the series drags on (and on...) so I would stick to the first dozen books or so.
Definitely, Little House books are great and appropriate for an 8 year-old. The Chronicles of Narnia are excellent, and it's a great introduction to CS Lewis. Most of his other works are often overlooked but are fantastic literature for older teens.
Other books include The Courage of Sarah Noble, EB White's books (Charlotte's Web, Trumpet of the Swan, etc.), and many mainstream books that are completely appropriate.
Keep in mind that reading some of the other items she likes is a great way for you to talk with her about your views on character, inner beauty, and integrity.