Ever since my two girls were easier to bring to restaurants, I have put together a list of restaurants to bring them to (aside from fastfood chains) when we go out. My girls are 4 and 6 so they are past the "highchair" size and the "walking around the restaurant" phase.
You will be surprised to know that coffeeshops (yes, drinks with caffeine which shouldn't be consumed by children yet) actually top the list! No, they don't drink coffee yet but most of the coffeeshops I frequent have cakes, pasta and sandwiches which they love heaps.
The picture is in Coffee Club 101 recently at the Robinsons Place Gensan. The coffeeshop luckily has juices and water, sandwiches and cakes. The seats are also kid-friendly! Low tables and chairs are what makes these coffeeshops great for with-children gimmicks.
Aside from coffeeshops, I like restaurants like our local Bigby's that has kiddie size meals and low-enough tables that enable my kids to seat properly and see their food while eating. They also provide activity placemats for children while waiting for our food to be served. What's more, they set the place for the child in your table. Some restaurants don't, assuming the kid does not eat. Duh.
So in summary, if restaurants want to be kid-friendly, in my opinion, they should:
1) Have a kiddie menu that adults can eat too, in case, the kid doesn't feel like eating the whole thing (well, actually, we like 'em kiddie meals a lot!) or at least have food that kids can eat easily on their own
2) Provide activity while eating (I don't like play areas in restaurants really because I'm training them not to go around when about to eat.)
3) Have low or high-enough height of tables and chairs
4) Have a wash area
5) Have, if possible, non-skid table tops and floors
Enjoy dining out with your children!