NYS may be a different situation than other states.
There are portions of the newer codes that NYS does not accept, such as the permission to use loadcenters with more than 42 ckts.
It is best to get the advice of someone who really knows how to apply the specific changes in the different code cycles for the jurisdictions one is working in.
In NYS, the best people to speak to are the State Officials in Albany. Even some of the Regional Directors of the state are unsure how to apply the electrical portion to the codes. I have had many, and long conversations with Albany, it can be frustrating.
Ed, just to let you know, I will stick my neck out and say the NYS is about to adopt the 2010 STATE CODE CYCLE. In this document, it looks very promising that they will apply the 2008 NEC for both residential and all other installations. Finally back to one electrical code reference in the State.
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P.S. - I have been spot on in the last two State Code Cycles...hopefully my source is still dead on )