Only you can decide whether it is worthwhile paying the extra for the 16-85mm.

It is better constructed and generally considered a very sharp, versatile lens. The 16mm wide-angle also gives it an advantage.

Most people will quite happily live with the 18-105mm and if you already have that as part of a kit, I'd probably advise saving your money for a flash or other accessory unless you really want the wide angle. For me? I started with the 18-55mm kit lens and wanted something better and love my 16-85mm and 35mm AF-S as my two most commonly used lens.

Being a slow'ish lens, the DoF meter on the 16-85 is a bit superflous.