thanks Fred, the 17-55 is a great lens for sure but more than 1k euros.. need to think on this matter before buying my next lens

I know this topic is a bit old but I'll answer it anyways since I had that doubt in my mind recently. Go for the Nikkor 17-55 like I did. It's a suberb lens. It has its flaws but it's the best you can find in that zoom range. Some say it's only a little better than the Sigma 17-50 2.8 and that it's so much more expensive that it's not a right choice to make but I didn't care. I didn't want to buy a sigma and then look at the images and wonder how much more sharp they would be with the nikkor.

Be aware that it's a DX lens and that its a professional grade lens, built with photojournalism in mind, meaning it's big, heavy and tack sharp in the f2.8 - f8 range and less sharp from that aperture on.

About the price, I bought mine used for about half the price you mentioned. Since it's a DX Pro lens, many photogs go for full frame and end up selling it.

The nikkor 24-70 is a great piece of glass also but on DX it's not with enough for full body shots, unless you have a lot of space.

Before the nikkor 17-55 I used a nikkor 18-70 but I wasn't happy with it at all. Maybe I had a bad copy or maybe mine was really beat up but I was giving me really soft images even at f8.