I love monograms, they are simple yet classy. Depending on the font style you use, they can evoke many different styles and tell you a little bit about the person to whom the monogram is attached.
I found this neat idea for an indoor/outdoor monogram plaque at The Pink Peony of Le Jardin. If you would like to learn how to make your own (she made hers for only 15 smackaroos!), click here for the full tutorial.