What camera are you going to be using the lens on?
I'd almost recommend either the 35mm f/1.8 or the 50mm f/1.4 paired with the 55-200mm f/4-5.6 VR. If you need something wider than the 35mm, the 10-24mm f/3.5-4.5 is fantastic.
If you get the 35mm, 55-200mm, and 10-24mm, you'll never need another DX lens, but they will run you about $1,200 ($200, $200, $800 respectively).
Also you will need an external flash if you need flash with the 10-24mm because of its size.
If you're set on a mid-range zoom, then the 18-70mm f/3.5-45 is a bit sharper. Then you can also pick up a 70-300mm for those long range shots. If you're going to be shooting on a camera with a built in focus motor, the 70-300mm f/4 is a killer choice if you can deal without having VR since it is only about $175.