The best button I ever saw said "Life" written on it. it was someone that was loosing a battle with cancer and it was there last big trip with the family. It actually was that pivotal moment where I started to do disney different because it made you step back and think how lucky you are to be able to appreciate the place more.
I would write in life also because I think that has a lot of meaning and denotes a passive enjoyment of everything around you and it really should be how everyone goes to disney. Enjoy the moment, it may not happen again.