Oma and Opa for my mother's parents. Grandma and Pappy for my father's parents. I asked my parents to pick what they would like their grandchild to call them, same with my in-laws. I think my mother will go with Oma, she told me she doesn't want to be a Grandma.

Since my SIL is having a baby next week I suppose whatever names my in-laws choose for her will have to be the same for us since it will be the same set of grandparents (my in-laws).