In my last trip i really felt the need for a little more zoom. There were place across trhe river which i wanted to shoot but was restricted to the 55mm length. Changing between the 18-55 and the 55-200 was a real tedious thing. I am now thinking of buying the sigma 18-125 as it seems to have better reviews than the 18-105. It would cost me around 25k. Other option is the 18-200.