First and foremost: I am NOT a salary and benefits expert...; ) Having said that---
If you are referring to all the known major cities in the US, you have to factor in the local cost of living for the areas in question. Generally speaking, the east and west coast areas of the US are known to generally have a higher costs of living (i.e.: apartment rent, real estate, taxes, etc.). Therefore, at least on paper, salaries offered at some police departments in these areas may seem to be, in comparision to other agencies say in the southwestern US (where cost of living may be less expensive), higher and more desireable. BUT, when you compare the two salaries, you're living equal lifestyles or levels of living. Some PD's also make up for what they might be lacking in salaries through benefit packages or other perks they may offer.
So, to make a long story short, $$$ does not always equal a better place to work! ;) Keep in mind that this a very broad speaking exampe and is, of course, my humble opinion about this issue...
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Charlie
"Good and evil are present in this world, and between the two there can be no compromise" - President George W. Bush, in his farewell address to the nation.