What should my next camera lens be?

I have a Nikon D3100, i have the 18-55mm lens that came with the camera and i also bought a 55-200mm lens a little bit after buying the camera kit.christmas is coming up and i'm thinking about asking for a new lens but i'm having trouble deciding what i should get… Should i keep going up to a 70-300mm or should i do something else. I like to take pictures of landscapes and flowers and other stuff like that. I mostly take pictures of my sister when she is dancing for the dance team any advice that you could give me on the next lens that i should get would be a great help.

The longer telephoto lens would have been a good option rather than the 55-200, but since you already have it, the additional value of the 70-300 is minimal. Get a wide angle lens.

The difference between 200mm and 300mm is not really that significant.

Lenses you may like are:

10-24mm super wide angle - good for landscapes
50mm or 85mm prime (non zoom) - good for portraiture. The 50mm is also a low-light lens.
40mm micro, 60mm micro, or 105mm micro - good for close ups of flowers or bugs.
70-200 f/2.8 - good for action and sports photography.

Your camera needs AF-S lenses to autofocus on your camera, so make sure those are the ones you buy.

I think you should get 50mm f/1.8G, it's great for low light, portraits, all around and other events. The 70-300mm is better but I think you should sell the 55-200mm if you plan on buying that one.

Here's a Lens Buying Guide - http://www.the-dslr-photographer.com/2009/11/buying-a-lens/