Good macro lens for Nikon D3100?

I have the Nikon D3100 with the 18-55mm lens and 55-200mm lens. I want a good macro lens. Is there any good macro lenses under $1000?

You will enjoy the AF-S 60 mm f/2.8 macro lens ($600) or AF-S 105 mm f/2.8 macro lens ($985)

I have the 105mm f/3.5 and use it a lot. On a crop-sensor, it about a 167mm tele, which isn't as long aas it sounds, but is handy. The advantage over the 60mm is greater subject-to-camera distance, but a lot depends on what you're shooting -- either is good.