Oz is an awesome name, especially when used as a short form for Osborn or Oswald.Names like these are particularly smart to choose for your son because he will have his full name to use in adulthood or professional situations, while his shortened name is fun, quirky, and can be used in childhood and around family and friends.
What a great simple name. I'm a huge fan of two-letter given names, especially when they are given at birth and not short for something else. Oz, Al, Cy, Ed, Bo, Ty, Jo - all wonderful on their own! Who needs the complexity of Osborne, Albert, Cyrus, Edward, Beau, Tyson, and Josephine?