Platform feeders can be simply be a sheet of plywood raised off the ground and covered with seeds, fruit or other food. A platform feeder about one foot off the ground is perfect for attracting birds that feed on the ground such as sparrows, doves or juncos. You can also hang a platform feeder from a tree or mount on a pole to attract a vast array of different birds. Again remember to look for protection of squirrels and ensure any wooden surfaces have been protected from the weather.
Hopper feeders are a bit more expensive but are usually easier to look after and come in a variety of interesting styles, including a Victorian house! The main advantage is this type of feeder automatically restocks the feeder until the feed has been exhausted from the hopper - this means you don't have to refill the feeder every day. Look for hopper bird feeders which hold a decent amount of seed and are easy to clean. You'll attract many kinds of birds with these feeders including woodpeckers, cardinals and jays.