Here's a new juvenile novel which is likely to be quite popular with girls: 3 Willows - The Sisterhood Grows by Ann Brashares. During the summer between 8th grade and high school three girls face different life-changing challenges that help to propell them toward adulthood.
Through each of their experiences the author shows young teens who are realistic. I think that 5th - 8th grade readers will fall in love with these characters and will want to hear more of their stories in future books!