Most re-read books

[ladyramkin2000]

All of Terry Pratchett's Discworld books.  They get better and better 
as they go on, and yield more with each re-reading.  Plus he doesn't 
keep you waiting for years between books and the quality of writing 
is by no means inferior to JKR's. (Admittedly there is little danger 
of him becoming pregnant).
Sylvia (who shares Carol's wish that something new could be 
discovered about Richard III.  Loyalty continues to bind me)