Barring the initial stages of introducing solid foods, my kids have always eaten what we've eaten. At first their portions contained less salt, but never less herbs or spice (unless we were eating something really pepper-y). I never understood why people would feed their children bland meals. (Do you like chicken with nothing on it?) Or worse, make something tasteless while the adults eat something yummy. I want my children to have a developed palate and experience lots of flavors, so after they were 7 months old, I stopped cooking them "baby food."
I grew up eating prosciutto, crostini di fegato, and bottarga; chawan mushi, sushi, and sashimi; kimchi, cool noodles and kalbi; peking duck, dim sum, and thousand year old eggs, and I want my children to do the same. My mom made almost everything from scratch from pasta sauce to Korean mung mean pancakes, and, a barring the occassional foray into boxed mac and cheese- and Morningstar Farm-ville (I'm no martyr, trust me), I strive to do the same. I strongly believe that cooking good, fresh food (it doesn't have to be complicated at all) is the way to teach children to appreciate and enjoy food.
I'm sharing this in case you are worried about what your children can eat. Of course, use your own best judgment, but my own kids have never had a problem eating adult food and my pediatrician actually encourages it. My mother-in-law has a peanut allergy, but around their first birthdays, they both tasted peanut butter sandwiches under careful scrutiny (and with 911 at the ready). They're fine. Reckless? Maybe, but how else are you going to find out? And waiting until age three for nuts? That's just crazy to me. (I do understand the medical reasons behind it, but still, crazy.)
I'm not quite sure how picky eaters are created (or if they are born that way), but I have my own ideas. In general, though, I think if kids are exposed to lots of different foods in an environment where they see their parents cooking and enjoying lots of different foods, that's half the battle. Not forcing kids to eat or playing other "food games" is also important. So is involving your child in meal preparation in age-appropriate ways.
Flip through cook books and cooking magazines with your children. Bunny loves doing that. She points to all the things she likes and we talk about what makes them so good. If you are lucky enough to have a garden that you eat from, I think that helps. (We have to settle for going to farmer's markets where the girls can taste everything.) Then again, kids really do have minds of their own, so who knows.
We don't have hard-and-fast rules about food in our house, but I do have guidelines I feel are important. We sit at the table and eat (no walking around with food). I serve lots of vegetables and fruits. We do try to limit sweets, but some juice is fine. We don't usually eat dessert, but when we do it's often fruit. They don't ever have to clear their plates, but they do have to taste new things (licking doesn't count). If they don't like what's for dinner and they are hungry they can have yogurt or an apple, but that option is rarely excersized. (I can think of one time Bunny went that route.) Of the combination of things I serve for dinner, they can usually find something they like to eat.
Both kids started out eating everything and then Bunny, my four-year-old, developed her own ideas about what she liked and how she liked them. She doesn't really flat-out refuse much of anything (cooked pineapple, bean sprouts, cooked spinach, and raw fish come to mind), rather, she's particular about how she wants it served: pasta without "too much tomato sauce," for example.
Wallie, my two-year-old (tomorrow!), still eats mostly everything, but we expect some pickiness to be rearing its head soon.
Why do I cook the way I do? It's partly for me and partly for my children. The fact that they will eat it? Why yes, I do feel lucky! And proud!