FUN FACT: Because of differences in international copyright law, THE BIG SLEEP by Raymond Chandler, one of my all-time favorites, is now in the public domain in many countries (including the UK and Canada), though not in the US.
Which means there's been a flood of international editions (now that the rights are free), and since the best way to differentiate your public domain title is an awesome cover, these editions have awesome covers. Which stinks if you're a descendant of the Chandler estate, but which is fun if you're a cover nerd, which I am.
These are three of my favorites. Behold!