Nikkor 17-55 f2.8 lens, and expecting to receive it in the next few days.
The 18-70 served me well during the 2 year that I owned it - first on my D70, and then for the past few months, on the D200. It is fast, wide, light in weight and offers a good zoom range that is ideal while travelling, or general walkabouts.
As of now, more than 90% of the work posted on my flickr account is taken with this lens. I had come to learn it's quirks and how to work around them. For e.g., it distorts heavily at the wide angle. In this photo, the nearest lamp post looks like it is curved instead of appearing straight. Nothing much can be done about it because that the nature of lower-end glass.
The 17-55, on the other hand, is a professional grade lens, and hence distortion should be minimal. I say "should", because I have not yet tried this lens, nor held it in my hands. I have simply ordered it based on the recommendations of fellow photographers.
Some people asked me why I would give up the advantage of the wider zoom range (18-70), and pay 4 times the price for a lesser zoom range (17-55). Well, it's true that I will be crippled because I do not have anything from 55mm to 80mm (My 80-200 f2.8 does duties from 80 to 200mm).
However, it's not just about zoom range. For e.g., for half the price, I could have picked up the 18-200 VR wonder lens. But what sets the 17-55 apart from all these amateur lenses is the constant f2.8 aperture for the entire zoom range. That means, whether I set the lens at 17mm or 55mm, I can keep the aperture at 2.8, which in turn, means I can shoot great photos in very low-light conditions.
At least, that's the theory.
And my 1300 dollars are riding on that theory.