You have gotten a lot of great advice so far. I wanted to chip in that while I don't strictly track some of the things you do (such as high fructose corn syrup) I feed our family of 4 plus for 5 days a week I also feed 3 extra kiddos breakfast, lunch, and snack. I spend about $100 a week at Hy-Vee, and that includes any diapers (I use cloth mostly), wipes for 5 little ones (I provide them for my daycare kiddos while they are here since I used them for after meal clean ups, tough nose clean ups, etc), and all our cleaning supplies. I buy a lot of generic items, but I do go for low-fat and "light" when I can. I buy meat when it is on sale and freeze it. I also keep most of our meals VERY simple. Having a busy husband, a busy teenager, and not having a ton of energy left at the end of the day, we only have a "big" meal once or twice a week. Otherwise dinner is simple like sandwiches, cheese tortilla roll-ups, grilled cheese, etc.
I make out my menu for each week including breakfast and snacks for the kids and make my list from there. Then we have certain staple items I restock each week as needed like bread, milk, sandwich meat, tortillas (seriously, we use them for SO many things!!), orange juice, etc. I also use coupons whenever I can.
There is the Grocery Game. www.grocerygame.com I believe, but not sure. I used to do it, but then when I had my son and soon after got very busy and frazzled with my daycare enrollment, I didn't have the time. I am going to start it up again. If you pick up the Sunday paper with that coupon booklet, Source, in it, as well as your own grocery store's weekly/bi-weekly ads, you are set! This site will give you a specific list of what the best deals are at your particular store. For example, say Source had a coupon for product A a few weeks ago, and this week your grocery store has that product on sale, it is extra savings over just using that coupon right away. Make sense? It is time consuming though as you need to clip any coupon you might need and find a way to store them so you can find them again, like one of those small accordian files (what I used). When you are getting a $4.00 item for mere penny's it is AWESOME!