Mariner's Harbor (I haven't linked to wikipedia here because the entry seems racist and I suspect contains and urban legend) presents the best neighborhood to look around at for cool old pictures and surviving old buildings. It's been a heavy industrial area, was and remains a working class neighborhood with an always diverse populations, and at one time was the heart of the Island's wealthy oystering community.
Because of various economic and demographic prejudices the Harbor stayed fairly intact (in regards to its older housing stock) till fairly recently. The beautiful big Victorian houses on along the north end of South Avenue were only demolished in the last decade or so (and even now one or two survive, crowded all around by the townhouses wedged onto the lots of their now lost compatriots). Even a few of the old captains' mansions along Richmond Terrace have stumbled along into the 21st Century.
Whenever I'm stuck for something to put up on the site I've been able to just troll through the Mariner's Harbor pictures on the NYPL site and just post away. I hope you enjoy the pictures.