Which do you think I should write first?

I'd really appreciate your opinion on which I should write first. :D

Peacekeepers- There is an otherworldly group of protectors over all humans. When one is sent to a human boarding school, he has no idea why or what will happen, only that something terrible will happen to change that world, if he doesn't stop it.

Ghost and human- After a long search, a ghost finally reunites with his true love. The only problem? His love can't remember him and is more than a little disbelieving of the ghost's story.

Poor vs. Rich- In the 19th century in another world, two young men, one selfish and rich, and another extremely poor and kind-hearted, are pushed together through forces they can't control.

Post WW3- Few are alive after the war. A small group of teenagers must rely on each other if they're going to survive.

Readjustment- After being found alone and having never had contact with other people, can they be rehabilitated, and even worse will they be driven apart?

All of my stories are slash and I plan on writing all of them eventually. Which one(s) you think sound the most interesting?