I have lived in Staten Island and California. I have always lived in nice but older communities, with lots of family nearby. If someone new moves on the street they often have several neighbors bring them "welcome" presents, the neighborhood list with everyone's name and number, ect. If someone goes on vacation there is always a neighbor willing to take care of pets, mow the lawn, get the mail, and water the plants. Christmas time everyone exchanges cookies, ect.
My brother lives in a small town in Missouri and they are even more tight knit.
Maybe it depends on what kind of area you choose to live in. I have never lived in a "newer" area and have gone out of my way to help out and get to know my neighbors. I think having a dog helps too since everyone sees you out and about, gives an opportunity to wave and say good morning/evening, ect. A sense of community is something that is important to me, so I go out of my way to find and foster it.
Having read this thread though I realize how very lucky I am to have lived in such neighborhoods.