For me - I like middle names to honour family members. DS's middle name Anthony is my DH's middle name and future children will also have a middle name that ties back with the family somehow (at this stage Joy is a definite if we have a girl after my deceased Nana). Funnily enough I use to hate my middle name as a kid, but have since grown to love it as I was named after a grandparent who I'd never had a chance to meet, and that to me is something special to link us I think.

I also agree with the middle name to differentiate it as well - I work in a bank and see so many people with the same first and last name - it's helped to keep them different by there middle name. Our last name is a rather common one (I remember one of the other staff served a girl with the same first and last name...at first I thought the staff member was looking in my bank details until I saw the middle name...lucky I'm a think before I act...could've easily gone over and given her a serve).