The Westing Game by Ellen Raskin- Delightful mystery. Definitely recommended.
The True Confessions of Charlotte Doyle by Avi- I read this one quite a few times as a child. Interesting and different, if rather unrealistic. I've also read Crispin and the Fighting Ground, but I didn't like them nearly as much.
Twenty and Ten by Claire Huchet Bishop- Lovely and short book about children in France who hide some Jewish children from soldiers. Very good.
Out of the Dust by Karen Hesse- This is a very good book. I need to read it again. Quiet and thought-provoking.
Caddie Woodlawn by Carol Ryrie Brink- Lighthearted book about a girl and her family living in Wisconsin in the 1800s.
A Single Shard by Linda Sue Park- This was a Newbery book a few years ago. Very good.
A Little Princess by Frances Hodgson Burnett- This is another one I read over and over. Like Laura said on her blog, it is magical when she wakes up to see her room completely changed.
Understood Betsy by Dorothy Canfield Fisher- This is a very good book about a girl who leaves one side of her family to live with other relatives that have very different views on raising children.
Blue Willow by Doris Gates- This is an older book that I read in the last year or two. It is about a migrant family in California. Recommended.