We don't need much either, but accept the fact that people want to get you gifts. If they get you things you don't need or want, return them, give them to charity...whatever. The gift-giver doesn't need to know. Also - I think there are some things everyone can use. You can't have enough sheets and towels, glasses always break, things you would never purchase for yourself, etc.
That being said, a theme shower may work better for you. It could be a lingerie shower, a kitchen shower (everyone brings a recipe and some type of gadget to make it with), a gardening shower - or somethign relate to whatever interests you and your FH may have.
As far as the wording on the invite goes, that's more for your MIL (or whoever is throwing the shower) to worry about. I'm sure there is some clever way to put in the invitations that you prefer gift cards, etc.