I think it’s more of a personal preference as far as 1 lens or 2 lenses that do the same job. I feel that the 2 lenses is what I would go for. That is what I have as a matter of fact. That way I keep the 18mm to 55mm on all the time. It’s less clumsy and not as heavy. Then when I know I’m going to be doing long distance shots I put on the 200mm lens. Then again the 18mm to 200mm will get you pictures of subjects that are very close to you as well as being very stealthy (is that a word?) from a long distance. Those surprise pictures are always nice ones to get. Just remember the larger the lens the longer it is and the heavier it is. If you take the camera pretty much every where like I do then you don’t want the weight. You can always zoom in and crop in photoshop later.