Asimov, particularly the Foundation & Robot series.
Heinlein, esp. "Something Wicked this Way Comes."
LOTR, every few years.
Dickens, "Tale of Two Cities."
I reread all the previous Harry Potter books every time a new one was to come out. I suppose now that she's finished the series I won't reread them quite as often.
"The age of Innocence," by Edith Wharton
Steinbeck, esp. "The Grapes of Wrath" & "Travels with Charlie."
Anne McCaffrey's "Dragonrider" series as well as any of the harper books.