I recently came across a copy of the Official USDA Food Plans: Cost of Food at Home at Four Levels. Considering the average cost of food in July of 2009, it breaks the cost down into four categories: Thrifty Plan, Low-Cost Plan, Moderate Cost Plan, and Liberal Plan. It breaks it down to age of child and age of man or woman and you can figure out what groceries "should" be costing you.
I figured it for us, using the Thrifty Plan figures. According to that, we should be spending $152.30/week, or $660.10 a month. Wow. My goal each month has been to keep it under/around $500. I guess I find this is a bit encouraging(since we've been close to that each month, but I haven't kept a close eye the last few months to be sure...) and gives me some perspective. I am really doing all right, at least according to the government's standards...
I think at the start of next month I will keep a closer tab on what I am spending, just to see for sure how I am doing.
Check it out for yourself and do the math and see what you can learn about your own food spending! :)