Yet another list of 10 books, created following Todd's suggestion.
You cannot beat a little dystopian reading to remind you how the world could change for the worse.
These are all quite popular and commonly read.
My favourite novel is tied between Lord of the Flies or I Am Legend both of them dark and brooding.
Scariest? Fahrenheit 451 wins hands down - I'm a bookworm, what would you expect me to say?!