Hi Markh, you'd think the 18-200mm VR may be compromised due to its long optical range, but it's actually very very good.
Have a look at the results and Gallery pages in our review here:
If you want a single lens to do it all and can afford it, then yes, it's the model to go for.
If you want a twin lens solution, then go for either the 18-55mm plus 55-200mm VR for a budget option, or the 18-70 plus 70-300mm VR for the quality option. If you're going for the D80 though, I'd sway towards either the 18-70 plus 70-300mm VR or the 18-200mm VR if you can afford it.
The 18-135mm is a really nice option as a budget single lens solution, but if you have a higher budget and or don't mind carrying two lenses, there's better choices.