I love the middle name to have a family connection. For DD1 it was simple, both my mum and MIL have the same first name, so we used that. For DD2, I chose her first name so I let DH choose the middle name, which was his grandmothers first name. If we have a boy we will probably use my dad's name as DH wants to name a son after himself, which is also his dad and great grandfathers name.