The front of your house is where you make your first impression. It's also the part of your home that everyone sees - including the ones that don't know you and only drive by your home. So don't neglect "decorating" the front of your home. One great way to decorate your front facade is with an attractive address plaque. See a variety of examples here.
If you have a brick or stone home, a stone address marker is a great idea. If you're building, talk to the mason about this. If you want to add it, you may still want to hire a mason to chisel out the necessary bricks and mortar the new plaque in place.
There are also bronze options that you can custom order for a very rich look, such as those at this site. Home Depot and Expo Design also carry brass plaques that you add numbers to yourself but look very much like custom plaques.
Another favorite of mine are custom ceramic plaques like these. You can order ones that you add the numbers to. You may also be able to make a plaque yourself at a ceramic shop.
The key is to pick an attractive plaque that fits the character and style of your home, that adds interest, and can also be seen from the street. While nailed up numbers will serve the purpose, there are many options today to display your address in style.