Ready? Here are some of the reasons why middle names are important:
Children often grow up disliking the first name they were given. If your child doesn't like the first name you chose, he or she has three options: bear it grudgingly, get the name legally changed, or go by his or her middle name. The last option would at least give you partial credit.
Speaking of credit, imagine that there are two million people with the exact combination of your first and last name on the computer that does VISA's automatic billing. If add in your middle name then your chances of getting an extra bill in the mail drops into the hundreds. So although the majority of people do not use their middle names on a daily basis, they are becoming increasingly helpful in computerized societies.
Middle names can also help a name flow better. Which sounds better: John Doe or John Tyrone Doe? Well you get what I'm trying to say.
My brother was given the middle name Douglas for no better reason than my mother thought it sounded nice, or flowed well in combination with his first and last names. I, however, was given David and Donald to go with my last name Donovan. Four names, three of them start with D, excessive flow there (actually in my case its called alliteration). My mother did have a reason though: she wanted to acknowledge my father and grandfather. So middle names can serve as a sort of dedication plate. Just don't try to acknowledge too many people.
Those parents with hyphenated surnames should be especially carefully of too many names. If your child ends up with six names the majority of them will not be used, let alone acknowledged, by that child.