Then, I remembered about a sling bag that was introduced to me many months back. It is known as Terminus EZ Body Bag. I found this bag to be very user friendly, light weight and spacious enough to put all my stuff without much issue. It can be carried on one shoulder or sling across the body.
The beauty of this bag is that it was designed for both right handed and south paw users. The bag has the same type of compartment which ever side you are carrying on your shoulder. Reaching for things inside the bag is much easier than a backpack because you just need to swing the bag conveniently around your body without needing to put it down.
I think it will make a good daddy/mommy bag, especially when you are going to places that requires you to carry walk a lot and carrying stuff for your kids. It is strongly recommended if you are planning to go to Legoland in the coming school holidays, or even Disneyland.