Last year I picked the story that I did because the kernel of it had been in my head for a long time but I had written none of it, and I decided that the NaNo project was a good time to try to get it out. So I think that this year I should also go with something that might never get written otherwise. I am considering several idea:
1) A sequel to last year's story. Though it ended in a way that didn't really demand a sequel, I am considering a second story where the "Dust" phenomenon that plagued the world in the first story gets worse and the protagonist rejoins his friend aboard the zeppelin and they have an epic adventure with great implications for the whole world. What those implications are will be determined about November 25 when I am entering the final sequence of the story.
2) A novel-length story set in the Aether Age milieu. The Aether Age itself should be available by then, and it might be fun to write an AeA story and perhaps post it as I go as another way to promote the real book. The problem with this idea is that I don't really have an idea yet for a new AeA story. I'm considering revisiting some of the characters and situations of the short story that I wrote for the anthology, but their tale might be too small-scale to go on for tens of thousands of words about it. So if I go with AeA as the universe for it, I'll probably pick a different situation and time period entirely. By the way, since AeA is a Creative Commons universe, anyone can write AeA NaNo novels, and it would be cool if someone else did. Who knows? We might even consider publishing it if it's good (I could see a short-ish AeA novel being half of an M-Brane Double sometime next year).
3) Neglected Project: A few years ago, my friend Pat and I mapped out the largest part of a science fiction epic, the premise of which is that there is a race of people who have based their entire civilization around using a technique of "quantum manipulation" to sustain the physical needs of their society. Over centuries they have built this into a religion where "penitents" "meditate" in huge cathedrals and cause things to happen in the objective world. To sustain this system, they have attracted other sentient races to live in their solar system and participate in this way of life, sometimes by literally relocating entire planets into orbit of their own sun. Among these people are the descendants of those humans who survived the destruction of Earth's solar system a millennium earlier. The story was intended to focus on a few of these humans and begins when aliens on another "brane" of the universe breach into our physical realm, causing epic calamity across dozens of worlds. The problem with using this project for NaNo, is that it would kind of be cheating since tens of thousands of words of it already exist in various forms. Also, it's too large-scale. There does exist within it, however, a couple of smaller-scale subplots that I could maybe extract and retool into a reimagined version of this otherwise probably permanently stalled project.
4) An erotic planetary romance. I've been tempted for a while to try to write an item with some of the flavor of an old Burroughs or Carter or Brackett sf/f adventure with things like an inhabited Moon and Martian princes and lots of gorgeous scenery and so on, but jam-packed with lots and lots of sex. This might be the project that I go with since it's one that I haven't even touched yet and may never get to unless I am "forced" to by NaNo.
5) A small-scale tale focused on a few people and the results of a natural disaster, sort of like Ballard's 1960s novels that Aldiss described as "cozy catastrophes." I'm not sure yet what the catastrophe is yet, but I am imaging a small cadre of purposeless, motiveless characters who gradually find some purpose as they contend with what's going on. This idea came out of a dream where I and others grappled with the fact that a huge section of ocean had opened up in the city, as if a portal had joined here and the Atlantic directly.
I'm sure I'll think of some ideas as the time approaches, but I'd like to actually outline something this year before starting. Not like I've ever outlined anything before.