For my trip to New York City I need a (zoom)lens with a wide angle. My current 24-70 (which is a great lens) doesn't give me the wide angle I need on a crop-camera. So I was looking for a zoom lens with a bit more wide angle.
The 17-55mm f/2.8 AF-S DX (etc) would suit my needs. Enough wide angle and a bit of zoom. No need for 100* zoom lenses because it's New York. Everything is cramped on top of each other. If I need zoom, I can always get a 1.7TC @ Adorama or B&H Photo in New York.
The 17-55 is bit on the expensive side (>1000 euros), so I rented it for the week @ Kamera-Express. Not that expensive, and now I got a decent lens for exploring New York. I just hope that the lens isn't that good, otherwise I need to have it ;-).