You already named all the good ones I know and have seen: Dr. Strangelove and Planet of the Apes (I was similarly knocked by its ending, and I had no idea!).

28 Days later...
That one was a pretty disturbing watch. Not for the faint of heart.

Twelve Monkeys
Terry Gilliam at work in his best form.

Of course, there's always The Postman, but I only recommend that those with sadomasochistic tendencies and a predilection for internal haemorrhages...