Oh wow! Funny to see this pop up again three years later. So, an update!
I put my kids in school last year (2010-2011). I had an infant and preschooler at home, and my kindergartener, 3rd grader, and 6th grader in school full time. It was a very very helpful break. The structure really helped our family. It turned out, I did have vit D deficiency, and SAD, and the chronic pain was fibromyalgia syndrome. We also discovered that my 4th child (who was then the infant in my original post) had colic and several food allergies (eggs, gluten, milk, almonds, soy, hazelnuts, and peanuts). My son was later diagnosed with high functioning autism. He did developmental preschool, and then was in the "life skills" classroom at his school. This year he was transitioned to a regular 1st grade class with a fabulous para-educator. We're getting all the supports from the school that I have asked for.
This year I have a 7th grader who is homeschooling, but also attending band at the local middle school. She has made lots of neighborhood friends and finally seems happy here in WA. My 4th grader loves school. My 1st grader isn't keen on school, but it is the best place for him right now. We do lots of "afterschooling" and ASD support activities at home, and would consider homeschooling in the future if school was no longer working for him, but would fight hard to make school work first. I don't know if we will homeschool our youngest two. My 4th child is still very high strung, and maybe she would benefit from school, but for now, we are waiting and allowing her to mature. And of course the baby is only 14 months, so she will be home for a good while yet.
I can't say I love homeschooling, but the mix of home and public schooling is working out just fine. It was a tough adjustment, to be on the school calendar, at first, but it works for us now.