I get the distinct impression that in LnC, Metropolis is supposed to be New York City, although admittedly that would be contradicted by Clark's sarcastic request to Lois that she speak up, since they might not have heard her in Gotham City -- Gotham City definitely being a stand-in for NYC. I know that other Superman venues imply or state it is elsewhere. http://en.wikipedia.org/wiki/Metropolis_*comics*#Location has several paragraphs discussing possible placements for Metropolis.

My favourite choice of locales is the Dover, Delaware area. According to http://en.allexperts.com/e/m/me/metropolis_*comics*.htm, (Please substitute open and close parentheses for the asterisks in the preceding URLs; the MB won't let me post this with the parentheses in the URLs.)
Quote
2006's Superman Returns places Metropolis as its own city (or state), unrelated to New York City or New York state. <snip> However, a map onscreen portrays it as possibly near or taking the place of Dover, Delaware."
I like that choice for two reasons; the first is that it would place it in my home state; but the second is because of the county Dover resides in...If you aren't a Delawarean, you might not know that Dover is located in Kent County!

I realize that the preponderance of the evidence places Metropolis elsewhere, but I thought you all might be amused about the county name. I must admit that nowadays whenever I hear Kent County mentioned in the news, it brings a smile to my lips...

cheers,
Lynn