Canal St just isn't really worth it anymore, and hasn't been in a couple of decades
Natural History - yep, goo - Metropolitan Museum of Art? Very good - no close public transit, BUT it's right across the park from Natural History - good excuse for a walk in the park
There are some good little "odd" museums tucked away in NYC. I don't know if it's still open to the public, but there was a little Museum run by the Bank of NY on Wall St - some interesting items in there
Here's one I always take people to see that almost NO one knows is there
When you got to Rockefeller Center, and you run from 5th Ave to the Alley that leads to the tree (the classic view), there is a building to your left (South) - GO INTO THE LOBBY - there is a silver model airplane there - LOOK AT IT - take you all of 60 seconds to get there, and usually gets more than a few gasps
Little Italy? OK I guess, but if you have transportation, go up to the Bronx, and go to Authur Ave
There are tours of Grand Central Terminal - worth seeing believe it or not
I personally never found The Empire State Building all that interesting
Statue of Liberty - Not all that interesting, and a PITA. If you want to see it close up, but not actually climb it, wait on line etc, just hop the Staten Island Ferry, and ride that both ways - this is one of THE best bargans in NYC - It's FREE
RE Statue of Liberty - I think Elias Island is a LOT more interesting
The Intrepid - If your interested in it, it is fairly good
If you're into Mideaval stuff - The Clositers up in Upper Manhattan