Well, it's not the most original reply in the world, but - my three kids (two grown sons and one daughter). Why? Because it's impossible to be emotionally bonded with a child from infancy, have that bond and the overall love for him/her grow as s/he grows and becomes more and more "his own person", and not recognize that powerful bond, urge to protect, and desire that s/he be happy and healthy as "love".
I once read that although there are, of course, different types of love in different kinds of relationships, one thing all love has in common is that it must include respect and admiration for the other person, includes wanting the other person to be happy, and includes a protective instinct.
Something else is that just loving them as much as I do (and always have) makes me happy. I don't want or need anything back from them (except, of course, respect - which everyone deserves). So, as I said, it's not original.