Exporting game characters to game engine, where should your point of origin be?

Before exporting your game model to a game engine such as Unity3D, lets say I created a human. Where should the point of origin be, should it be between the bottom of the two feet like this?

After exporting it to Unity3D, then if the feet are completely inline with the ground (lets just say that the ground on the y-axis is 0 (Unity uses left hand coordinate system so y-axis goes up and down unlike Blender) as well as the feet), would my animation work correctly, would the feet be stuck in the ground?