Not to be combative at all, but there has been more recent studies that have made pediatricians look twice at the whole ADD/food additive issue.
http://www.feingold.org/Research/PDFstudies/AAP08.pdf
I would post the direct link to the American Academy of Pediatrics site, but you need a subscription to view. Some children (like my own) have an actual neurological reaction to the chemicals that are in our food. When my daughter was in kindergarten, the teachers told me that she had the intellectual level of a 3 1/2 year old, but I knew she knew the answers to the questions they were acting when we did them at home. She could just not focus at school. I, too, struggled with the medication issue. Then I found Feingold. I figured what could it hurt to give it a try? My pediatrician all but called me crazy and a bad parent for depriving her of these foods. (I guess feeding my child grilled chicken and broccoli instead of chicken nuggets and french fries is bad parenting). So, against his advice, I tried it anyways. What happened over the next 3 weeks was nothing short of miraculous. All of a sudden I had a child who could pay attention, was social with others, and behavioral difficulties almost completely disappeared. What sealed the deal for us was when her speech teacher accidentally gave her a single marshmallow (they have blue dye in them to make them appear whiter). She turned into a complete monster before the teacher's eyes. Turned everyone in the school into a believer!
Ever since that incident we have been additive free. DD made up a year and 1/2 intellectually in the 6 months that followed. That was 2 1/2 years ago. She still struggles with focus issues at times, but she is very smart and has scored around 100% on all of her spelling tests this year and just brought home a math test where she scored 95%. So, for us, the ADD was mostly a constant reaction to the foods she was exposed to. Oh, and I then fired her peditrician.
To OP, I wish you all of the luck in the world in your decision. I know this is a very difficult decision for any parent. If the diet wouldn't have worked for us, I would not hesitate to go the medication route. There is nothing worse than to see your child struggle. To BeckyScott, if you want any more info on my Feingold experience, feel free to PM me.
Michelle