What kind of bird feeder should I get? This is difficult to answer because there is no single best bird feeder. Even a simple tray will work. Or, you might opt for the other extreme and get an expensive, architecturally detailed feeder. The only real requirement is that the feeder be installed in such a way to prevent predation from cats or other predators. If any feeders are near house windows, make sure those windows have decals or tape to avoid bird strikes.
Once the above two situations are satisfied, look at feeders that are easy to clean and that will discourage squirrels and other freeloaders. Many tube feeders now feature removable bottoms to make cleaning easier. Others offer a wire mesh guard, which prevents squirrels from eating but allows small birds to enter and feed. Look for a feeder that is tall enough so that squirrels can't hang from the top and eat. There are other, more "active" feeders which are effective against squirrels. These feeders have a spring-loaded perch which closes the feeding ports when a squirrel sits on the perch. Another popular line of feeders also offers spring loaded perches that collapse under the weight of a squirrel. Thus, the squirrel has nothing from which to hang.