There are a lot of good walkaround lenses. The best depends on what you like to shoot and how much you can spend. Most start at 16-18mm on the wide end. The big question is how long (telephoto) do you want? Do you find yourself switching back and forth between the 18-55 and 55-300 or do you use mostly one or the other? Do you find yourself shooting at or near 300mm a lot?

If you seldom shoot near the 300mm end of the 55-300 you may be happy with the Nikon 18-140 VR or 18-200 VR. If you do shoot near 300mm then a Sigma 18-300 Macro would be a good choice. It's my walkaround lens. It's very sharp, well built, and a lot less money than either Nikon 18-300.

If you seldom use the 55-300, don't buy anything unless you shoot in low light without flash. Your 18-55 VR is a very sharp lens, but a little slow. For shooting in low light without flash a Sigma or Tamron 17-50 f/2.8 would be a good choice.

A note about superzoom lenses like an 18-200 or 18-300 is that they are not as sharp as using a pair of lower ratio zooms like the two you have now. Some find them sharp enough, some don't. IMO, if you don't print much larger than 8.5x11 or if you only view your photos electronically, you probably won't see a difference between a good superzoom and comparable shorter ratio zooms.

Another suggestion is to get a copy of "Nikon D7100 Digital Field Guide". It's a better manual than what came with the camera, and its a good basic guide to photography geared specifically to your camera. It also has a good glossary of digital photography terms. There are other good guide books, but this one is especially good for newbies.

There are a lot of good walkaround lenses. The best depends on what you like to shoot and how much you can spend. Most start at 16-18mm on the wide end. The big question is how long (telephoto) do you want? Do you find yourself switching back and forth between the 18-55 and 55-300 or do you use mostly one or the other? Do you find yourself shooting at or near 300mm a lot?

If you seldom shoot near the 300mm end of the 55-300 you may be happy with the Nikon 18-140 VR or 18-200 VR. If you do shoot near 300mm then a Sigma 18-300 Macro would be a good choice. It's my walkaround lens. It's very sharp, well built, and a lot less money than either Nikon 18-300.

If you seldom use the 55-300, don't buy anything unless you shoot in low light without flash. Your 18-55 VR is a very sharp lens, but a little slow. For shooting in low light without flash a Sigma or Tamron 17-50 f/2.8 would be a good choice.

A note about superzoom lenses like an 18-200 or 18-300 is that they are not as sharp as using a pair of lower ratio zooms like the two you have now. Some find them sharp enough, some don't. IMO, if you don't print much larger than 8.5x11 or if you only view your photos electronically, you probably won't see a difference between a good superzoom and comparable shorter ratio zooms.

Another suggestion is to get a copy of "Nikon D7100 Digital Field Guide". It's a better manual than what came with the camera, and its a good basic guide to photography geared specifically to your camera. It also has a good glossary of digital photography terms. There are other good guide books, but this one is especially good for newbies.