My fiance and I have done a very small registry on amazon.com for those who really want to get us a gift. However we don't really need anything and just prefer to see our families.
I know not to talk about gifts on the formal invitation but I was just going to put something on our website like:
"While your presence at our wedding is the only gift we ask for, we have registered for a few things just in case."
Is that rude? Of course gifts are always appreciated!