We had a rare visitor on the suet feeder a couple of days ago: a red-bellied woodpecker. We have my DH to thank for the photo, which he took with his hi-tech zoom camera.
Most of the woodpeckers we see on our feeders are hairies and downies. They have an annoying habit of completely emptying a sunflower seed feeder by pulling out the seeds one at a time and dropping them onto the ground uneaten. I don't know how much the ground-feeding juncos and doves are paying them to do this.