Story Plans

Every morning before work I try to write a little towards my daily target. Some days I manage to get a decent amount done, while on others I just cna't get my head-gears working. Today was one of those other days, brought on by my third or fourth encroaching head-cold this year and something weird going on in my shoulder.*

So instead I tackled the story plan for my new book, which I started weeks ago and hadn't finished yet. It's still not finished, but there's a lot more structure to the story now and I've nominated the key events that will mark the bridges between Acts. This is the first time I've put this much formal planning into anything I've written. It feels good to have a series of goal points to mark my progress, rather than just trudging through the story trying to reach the ever-elusive climax.

How do you guys feel about story plans? Do you find them useful, or just like to see where the writing takes you? Do you also use a 3-Act structure?

*I'm ridiculously run-down these days. I've not been sleeping well.