When to Stop Planning and Start Writing

Sorry for the bit of bloggy silence guys. The school year is winding down (only 2 weeks left!!!) and things are a little crazy. I have tons of testing and data stuff to do before the end of the year. It's been nuts, so posting may be slightly sporadic for the next couple of weeks, but I'll do my best!

Anyway, I've mentioned before how I'm working on my latest novel. I've been doing tons of plotting, planning and story boarding. With my first novel I just sat down and wrote. It went really well until I was about 2/3 of the way through the book. Then, I got stuck. I had no idea how to get from where I was to the ending that I envisioned. I faltered and eventually set the whole manuscript aside. With this book I was determined to be different. I've read tons about plotting, structure, character development. I've got a notebook full of ideas, plot lines and my story board (as seen at the right). I was bent on having every single scene for my novel plotted out before I wrote the first sentence.

This went well as I plugged along through the first act. I had all of my scenes laid out, scene cards done. I had character sketches and setting sketches and I was ready to rock and roll with my second act. And....I hit a huge block. I had no idea what my characters were going to do next. I sat at Borders with Cari, my lovely critique partner, for a week doing generally nothing.  I stared at my sticky notes and flipped idly through my notebook, and made a big production of drinking my coffee. I whined at Cari, and bless her soul, she finally shut me up and told me to just start writing.

I did, and finished my first chapter today. It's not pretty, but it's on paper and a first draft is done. I'm still feeling a little daunted by the second act, but I'm getting there and I at least feel like I'm making some progress.

So my question is this, how do you write? Or do make any decision. My husband is currently over-thinking what car he's going to buy. :) Do you just start writing? Plot is all out? Some combination of both? How do you decide when you have planned enough and just jump in?