Some of my suggestions were already mentioned so how about:
The Bridge To Terabithia
The Catcher In The Rye
A Separate Peace
Hatchet by Gary Paulsen was one of my absolute favorites as a boy. I read a lot as a kid though, so I don’t really know what grade level the book is.
I read it in 4th or 5th grade as an assigned book. I second the recommendation, assuming that it’s interesting for 7th graders and hasn’t been assigned.
Let me just second this one.
In 7th grade, I loved The Human Comedy by William Saroyan. You can’t go wrong with Harper Lee’s To Kill A Mockingbird, though it may already be on the curriculum.
Also, there’s the book I’m currently in love with, so I can’t resist throwing in a plug. It’s a one-man play by Glen Berger called Underneath the Lintel. It’s about a librarian who finds a book that has been returned 113 years overdue and embarks on a quest to find out who took it out. I recently saw it with Richard Schiff. This review of the production I saw can give you more information about the play. It’d be a short read, 4 or 5 sessions at most, but the kids will love it.
More Terry Pratchett for kids: The Johnny Maxwell books. Pratchett’s always good for a read-aloud, and these combine supernatural/SF elements with gritty realism about the lives of boys in the British Midlands.
Eva Ibbotson’s Island of the Aunts. Part of the review from my library web site:
The island’s caretakers–three eccentric, kindly aunts who are getting on in years–need younger, able-bodied helpers to continue their mission: tending the injuries of unusual creatures (gigantic birds, talking seals, mermaids, etc.) who have been harmed by mankind. Resorting to desperate measures, the trio travels to the mainland to kidnap suitable candidates (“Of course it won’t be a real kidnap because we shan’t ask the parents for ransom”). Two of the abducted children are not sorry to leave home; they become fond of the island creatures and their captors almost immediately. But the brattiest, most spoiled of the three is intent on returning to the comforts of his mansion. Tension mounts when the children’s whereabouts are discovered, putting at risk the island creatures’ privacy and safety.
Also The Wee Free Men . But you had better have a limber tongue when you vocalize the accent of the Nac Mac Feegle. 