ahhh the traditional card writers panic ... must be original must be original etc.
how about a quote
"Don't be dismayed at good-byes. A farewell is necessary before you can meet again. And meeting again after a moment or lifetime is certain for those who are friends." Richard David Bach
"Goodbye, goodbye, I hate the word. Solitude has long since turned brown and withered, sitting bitter in my mouth and heavy in my veins."
R. M. Grenon
"'It is never good dwelling on good-byes, It is not the being together that it prolongs, it is the parting.'"
Elizabeth Asquith Bibesco
think that would add a little class to the proceedings - or make you look a little silly, who knows, i generally just go with "best wishes and all the best etc etc etc have you gone yet, no? then mines a pint cheers"