So you're saying your 200mm zoom is better than his 200mm zoom. In context, his is a better zoom than yours because it has a zoom range of 3.63:1, whereas yours is only 2.85:1. In absolute terms, you both top out at 200mm so are identical. I'd also wonder about your classification of the 18-200 as a "consumer" lens: the technology is no different to that in any other recent Nikon lens. What would be the "pro" alternative at this point? I guess maybe the 18-200mm VR II, which is actually optically and VR-wise identical apart from the zoom lock at 18mm. Announced July, available September, and I've played with it.
Given the range of advice JOFM has received so far, I'd actually narrow my own suggestions to one item: if JOFM shoots outdoors, buy an expensive circular polarizer without telling anyone, and report back in a month.