What's the best gift a parent can give to their child?

Best gift? For me it would be the gift of understanding. Of letting your child know and feel that you love him and you accept him for all he is and for all he will be. Of course this comes with proper guidance and letting him discern on his own. By being understanding, you are also building his trust towards you. Now if it's something tangible, a warm hug would be the best. It's not just something that he can see but it's something you can make him feel.