Funny, I was just working on organizing quotes by topic and remembered seeing that one go by.
Quote:
Death is nothing to us, since when we are, death has not come, and when death has come, we are not.
--Epicurus (341 BC - 270 BC),
from Diogenes Laertius, Lives of Eminent Philosophers
I don't know which movement Epicurus is considered to belong to, but you'll undoubtedly find that fact buried somewhere in this excellent page:
http://www.utm.edu/research/iep/e/epicur.htm