Great idea for a thread! Ds11 was and is a big fan of Ender; has your ds read 'Ender's Shadow'? It's the same story, told from Bean's point of view. There are lots of sequels too, some of which ds has read and enjoyed.
Two other series that were and are still favorites:
Mortal Engines and its sequels and prequels, by Philip Reeve (postapocalyptic, big and sprawling and imaginative, with male and female teen protagonists)
His Majesty's Dragon and its sequels, by Naomi Novik (think Anne McCaffrey meets Patrick O'Brian; written for adults, but ok IMO for kids; not as violent as Ender, and only a few vague allusions to sex)
More suggestions from ds:
Asimov's I, Robot
the Asterix series of comic books
Bone, by Jeff Smith
a younger series by Philip Reeve that starts with 'Larklight'
Eragon
Redwall
several of Michael Crichton's books (Jurassic Park et al.)
Susan Cooper's Dark Is Rising series
Anthony Horowitz's Alex Ryder series
James Patterson's Maximum Ride series
Terry Pratchett's Discworld books (there are almost 40, so here's a reading-order guide:
http://www.lspace.org/books/reading-order-guides/the-discworld-reading-order-guide-20.jpg)
Hitchhiker's Guide to the Galaxy, by Douglas Adams (excellent audiobook by Stephen Fry)
ETA: any of the Dilbert books by Scott Adams
Berke Breathed's Bloom County comics
Erin Hunter's Warriors series
Hope this helps --
