I recently connected online with Stephanie Gallagher, and she and I share a similar view. Her philosophy is "if the food tastes good, and it's eaten together, the rest will generally take care of itself." She writes about about kids and eating and posts recipes on her site: http://kidscooking.about.com/. I'd recommend checking it out.
So if you're really concerned about what your children are eating, my strongest recommendations would be to do your best to prepare meals that taste good and then eat them together as a family. When you prepare meals at home, you have greater control over the ingredients and can make choices based on taste preferences and health concerns. When you eat together, your children have better odds of eating more fruits and vegetables and less fried food and soft drinks. When you are planning and preparing your children's meals, you're acting as their "nutritional gatekeeper" - deciding what they can and cannot have access to.
By making decisions about what foods are brought into my home, I make decisions about what foods my kids can or cannot have access to all the time - although they may not always realize it. Each weekly trip to the grocery store involves numerous decisions about what to bring into the house. Will I spend the extra money on organic produce? Sometimes. Will I buy sugared cereal? Rarely, but Santa and the Easter Bunny bring them as treats. Will I buy my daughter her favorite lunch meat - bologna? Once in a while. Will I buy chips? Sometimes. What milk will I buy? Either 1% or 2% depending on the expiration date and organic availability. Weekly menu planning also determines which meats and non-meat proteins they'll be having.
Take your "nutritional gatekeeper" role seriously! Researchers estimate that parents control about 72% of what their children eat*. As a developmental psychologist, I would predict that the percentage varies with age. Establishing good nutritional habits when kids are young increases your chances that they'll carry good habits with them as they grow. But also take yourself off the hook. Notice that the number is not 100%. Do not feel that you can control all of your children's nutritional health. You're more likely to feel frustrated and get into battles with your kids if you think you can control it all.
*Wansink, Brian (2006), “Nutritional Gatekeepers and the 72% Solution,” Journal of the American Dietetic Association, 106:9 (September), 1324-6.