Is Money an Impersonal Gift for a Graduating High School Senior?

We have a couple of friends and relatives with kids graduating high school this year. I'm never quite sure what to get a graduating senior as a gift?
I know that they probably need money for going to college, traveling, or getting the boot from their house. Money just seems so impersonal.
Is it ok to give money as a gift? What do you get a graduate as a gift?