My oldest(of 4) is 17 years older than the youngest. He's actually her Godfather! The age difference was so great, we thought it would be a nice touch to give them a "special" relationship, since he's more of an uncle figure than a brother. He's lived on his own most of her life.
That "second wave" of childrearing can be a trip. With age comes wisdom (most times) but there's no substitute for the raw, endless energy of a young Dad. At 48, having a 10 year old is not as easy as it was when I had a 10 yr old at 31 !