"I told my wife - the best thing to get an 18 year old for his birthday is suitcases."
My Dad gave me a ride to the recruiting station.
At 18, you can offer your kids a couple two options: (1) partial/full college financing, or if they don't want to continue their education (2), seed money to get their first apartment (or a ticket to the recruiting depot).
You'll never be able to have a cool parent/gown kid relationship until they get out there and grow up.