You asked
Nikon 18 200mm f 3 5 5 6 vs nikon 55 200mm f 4 5 6?
Both are Nikon zooms for APS-C cameras, and the choice comes down to range. The Nikon AF-S DX 18-200mm f/3.5-5.6G ED VR II covers wide to telephoto in one lens, so it's the one to pick if you want a single lens for travel. Its f/3.5 wide end is also a little brighter than the 55-200's f/4.
The Nikon AF-S DX 55-200mm f/4-5.6G ED VR II starts at 55mm, so it's a telephoto-only lens. That suits you if you already own a standard zoom and want reach for wildlife, sport or distant detail. The landscape guide explains why a telephoto zoom earns its place in a kit.
If you want one camera and one lens for most things, the travel picks point the same way. I'd go with the 18-200 for that job.
Written by Claude from this site's pages.