As someone who lives in "the country", I often hear people from heavily populated areas saying that it would seem a waste of time to bother putting up any type of bird feeder. On the surface that may make sense, however I always disagree with them. Living in a rural setting can sometimes make it harder to attract birds to a bird feeding station. I have personally put out many types of seeds and feeders only to watch them sit for days without any birds using them. Other than pesky squirrels that empty them and the occasional bear.
Keep in mind that birds that inhabit a rural area have a much wider availability of natural food sources. Within a few miles of my house for example there are many farms and wetland areas. These habitats provide a vast supply of food. Birds do not have to seek out my bird feeders. They can easily feed on the left over corn and other grains that are left after plowing the nearby fields. There are also worms and insects in abundance.
City dwelling birds do not generally have these food sources readily available. They may take longer to locate your feeding station but will soon become regulars. You may have to get creative in placing your feeding station due to lack of space. The use of a window type feeder may be used in the case of apartment or condo type dwellings that are commonly found in cities like New York. Although the simplest of feeders they can provide a close up look at birds. Feeders can also be attached to decks or even the sides of buildings with permission.
Keep in mind that many cities are have park areas that different types of birds are sure to live in. Some cities are also located in major migration routes. New York is a great example of this, New York is also close to the wetlands of NJ so there are plenty of interesting birds to attract and feed. These areas also make for great birdwatching as well as other types of wildlife watching.