Wow. sherlocked, you must have some stunning students. Btw - just checking you got this straight - I'm not the OP; the fact I mentioned the Simpsons was just me thinking out loud.
They really enjoyed reading the Canterbury Tales in the original at 15? Wow.
I do think that hobs has it right here - there is a big difference between enjoying a text in class, and reading it outside of class. My take on the OP was she wanted books 'other than' the set texts?
I think there is too much emphasis on reading and not enough on performance here - I was thinking, if you don't fancy Shakespeare in performance, I bet you could get tickets for some more modern plays?
Btw, these are mostly very 'male' lists we're coming up with - could that be the problem? She might want to look at Virginia Woolf, or Mary Wollstoncraft, or Caryl Churchill, Wendy Cope? Or novels by AS Byatt, Margaret Atwood, Penelope Lively?
I think as sherlocked says, we need to know if you want to shock her with a syllabus or if you want to encourage her to read outside her own current syllabus (or both). Both will be expected of English Lit students, but in slightly different ways.