The American Book Review has a list of the "100 Best Last Lines from Novels" (PDF). Obviously, this means some spoilers, but cautious browsing can avoid that. Their list of the "100 Best First Lines from Novels" holds no such perils.
This comes via TBogg (in turn from Matthew Yglesias, whose commenters make other suggestions). TBogg has a post soliciting suggestions for the best last lines from short stories. Check the comment thread for many reader submissions.