everyone here almost is quick to diss the 18-200. i know its not a gold ring lens or a top end lens... but its not a low grade kit lens like the 18-55...
Ehm... The "low grade kit lens" 18-55 actually performs better in that interval than the 18-200mm, as far as I know. The 18-200 is much more expensive, but that is because of the zoom capabilities - not because it would be any sharper or have less distortion in the focal range 18-55mm.
It would be wrong to assume that everything expensive is better for all purposes than everything cheap. The phrase "you get what you pay for" is usually wrong, in my experience.
Some people always go for the cheapest of everything, because they cannot afford anything better. I guess that is an ok strategy.
Some people always go for the most expensive of everything, because they assume that must be the best product. That is irrational.
Some people ignore the prices of everything completely. They check out what is best for their particular needs. Then they check the prices, and remove everything they cannot afford from the shopping list. I guess that is the most efficient strategy.