A quick and dirty summary of Nikkor terminology (you might want to check out
www.nikon.com.sg too):
D: distance chip incorporated into the lens for 3D matrix metering and flash.
G: same as D but lens lack an aperture ring, making it having only limited functions with some of the older Nikon cameras
DX: line of Nikkors specially designed for the digital format. May not be able to generate a full frame picture on film format.
AF-S: incorporating Nikon's Silent Wave Motor, leading to extra fast focussing. Similiar to Sigma's HSM and Canon's USM.
VR: Vibration Reduction technology. Allows 2-3 stop gain in shutter speed. Also equivalent to Canon's Image Stabiliser lenses.
ED: Extra Low Dispersion glass for inceased colour contrast, reduced chromatic aberration.
Note that 'do-it-all' zooms, such as 28-200mm (Sigma,Tamron and Nikon both have these) are usually lacking in optical quality...but you have to try them yourself to see if you can take the quality tradeoff. Also if you are using a Nikon DSLR, the 28mm isn't going to be very wide.