Hello All - I'm a Canon lover but a good friend of mine asked me for a recommendation for a lens for his Nikon. I turn to you Nikon Gods here for advice. He is going on a trip and wants one good lens to take with him. I figured something 18-200 (or 300). I know it can be hard to get just one perfect lens that can do all things equally well, but if you had to pick just one lens what would it be? Budget: try to keep it around $300-$500 please.