When I decided to get some bird feeders, I really didn't put a lot of thought into it. I just went to Walmart and grabbed a bunch on inexpensive feeders. My main criteria at the time was cost, perceived effectiveness to attract birds, and ease to use.
I ended up buying 1 hummingbird feeder in the traditional red and clear plastic, 4 plastic tube type of seed feeders, and 3 suet wire feeders. Grand total was approximately $40, not including feed.
I started off attracting some interesting species: chickadees, titmice, nuthatches, cardinals, house finches, hairy woodpeckers and a red-bellied woodpecker. Before long there was lots of activity on the feeders with the addition of cowbirds, mockingbirds, English sparrows and squirrels. Lots of squirrels.