Zeldman
Touchdown! Greaser!
I always tip a $5 at airports (not at home as I use the self service). I was amazed at the great service I got when I first started. I asked several linepeople after I did it and they said that they are used to getting nothing.
Don't forget the line guys. A few times when I didn't have cash I would send a pizza over, making sure my N number was on the box.
They will remember you.... one way or the other...