The end of the world

I realized that there are so many different apocalyptic scenarios in our pop culture.

The Zombie Apocalypse - found in numerous books, movies and video games.

The Robot Apocalypse - made famous by the Terminator and Matrix movie series, as well as the many books.

The Dragon Apocalypse - most notably in the movie Reign of Fire.

The Vampire Apocalypse - the movie Daybreakers comes to mind.

The Alien Apocalypse - another popular one found in many books, movies and television shows. (this on can be broken into a dozen or so sub-scenarios, including alien invasion, body snatchers, alien virus and I guess you could include The Blob though I'm not quite sure what that falls under.)

I'm adding a poll for you to help me figure out which would be the worst one to attempt to survive. I have my opinion, of course, but I want to now what others think.

My Opinion, in order of worst to easiest.
Zombies - Billions of undead people trying to eat you, the odds aren't in your favor.
Dragons - They are freaking Dragons, they fly, breath fire and can destroy a city in seconds.
Robots - They are cold, uncaring machines of death, but they are just machines.
Aliens - They cause untold damage and kill thousands, but they always are defeated by something simple.
Vampires - They don't go out during the day, and have a fear of garlic. Shouldn't be too hard to survive this.