I too agree with ssmith... a card maybe with your own words in it. For example, I gave my mum a beautiful white stone on the Mother's Day, and of course, a poem - It was all metaphor. My opening line is,
Not a usual gift. Not a card.
I will give a white stone.
Round like a heart....
Read it, if you like
Even though, you'll give you-know-who a simple gift like a stone, it would create a lot of difference if you'll also hand in a beautiful poem that would explain your feelings to him/her without being so cheesy.