pcristao - Here's the gothca on your question:
The 18-200 is pretty sharp on the wide end of its focal range. It's lack of sharpness doesn't really set in until 100mm or so, and isn't noticeable until about 150mm. Even then its still really good... just a bit soft in some circumstances.
The 16-85 is pretty sharp across its entire range (from what I have read I don't own it). It's softest at 16mm and gets better from there.
If you want to shoot wide angles, the 16-85 is better, but not much better. You get about 7 degrees more (3.5 on each side). If you want to shoot in the mid range... say 85mm, both lenses are about the same. If you want to shoot something far away, the 18-200 is obviously a better choice because the 16-85 doesn't go any further than 85mm. Of course if you knew in advance that you would be taking telephoto shots, you'd be better off with the 70-300 anyway. It is sharper at 200mm then the 18-200, and it has more range still.
That gets me to my point. The reason to own either of these lenses (16-85 or the 18-200) is for the flexibility they offer. If you are only going to carry one lens... it would be one of these two. As part of a set though, I'm not sure I'd use either of them. The 18-55 is sharper across its entire range, and only costs $100 or so ($80 used... and there are lots of them). You could use the savings to grab an ultra-wide angle like the Tokina.
So to summarize, a Tokina 11-16mm + Nikon 18-55 & Nikon 70-300 lets me shoot just about anything (throw in that 35mm prime for times when sharpness matters or you need to shoot in poor light). This is sharper and more versatile as a whole then the 16-85 + the 70-300. It's also better than the 18-200 + the 70-300.
If you like being prepared for the unexpected, then you may not want to be fumbleing around with four different lenses. In that case, one of these zooms will suit you well. The 16-85 is sharper, and the 18-200 is more versatile... pick your poison.
Still confused? Check out these two guys for differing opinions and decide for yourself: