I came from a D40 to the D7000. You are in for a wonderful surprise. Gone are the days when it seemed the camera just didn't to want to focus. The picture quality of the D7000 will amaze you.
I think you are going to like your new camera.
On the lens issue. This past spring my wife and I traveled to Hawaii. Because of weight and space, I only took the D7000, the 18-200 lens, a 35 mm f1.8 lens for evening shots.
95% of my shots were taken with the 18-200mm lens. The 18-200 lens is a good all around lens that will give you many many great shots. If it gets dark...just put the camera and lens on a tripod.
BTW - For the trip to Hawaii, I took along a GrizloPod. It looked goofy and I had to get on my belly sometimes, but it and the D7000/18-200 setup took some great pictures in Hawaii. Here is one, to show what the combo can do.