Registries are incredibly organized and helpful, and it is not "greedy" to register. Most guest find registries a very efficient way to select a gift that the couple would like, would need, and that wouldn't be duplicated by other guests. While it's okay to have more than one registry, draw the line at three. You want to be helpful by offering your guests variety, not self-indulgent by listing your every wish in the world.
It's fine to have a less traditional registry - one with gardening equipment or camping gear - but include a traditional one, too, even if it isn't very full. Many guests, especially older ones, will feel much more comfortable with a few classic options. As shower gifts are typically less expensive than wedding gifts, it might be a good idea to set up a shower registry separate from your wedding registry with lower-priced items, especially if there is a shower theme.
The best registries have a mix of both prices and types of items, so that all of your guests will feel comfortable finding something they will be excited to give you.
Just remember: in the end, the choice of gift is always up to the giver, so great-aunt Edna might still buy you a blender.