My memory is shit, so I'm probably heavily influenced by what I've read on here already, but I agree that The Stand is brilliant, I loved it when I read it as a teen.
I loved Wild Swans. I love a good history written as fiction book, so I also loved Wolf Hall and Memoirs of a Geisha. Also, I like the James A Mitchener books about countries, particularly Poland.
I hardly ever re-read books, but I recently read Wuthering Heights again and loved it.
We Need to Talk about Kevin mentally scarred me, I probably shouldn't have read it just after giving birth to a boy! Great book though.
Oh and of course, To Kill a Mocking Bird. It deeply affected me when I read it in my early 20s, as did The Colour Purple.
I remember sobbing on the tube whilst reading Watership Down 