Each year I debate deadheading my coneflowers in the front yard. I know the birds love the seeds that form after the flower fades, but I also want a tidier look in the front yard (I never deadhead in the back). Then every year the goldfinches remind me why it's OK to be lazy with the front yard coneflowers.
Goldfinch on Echinacea purpurea (Purple Coneflower)
The American Goldfinch survives almost completely on seeds, with a cone shaped beak to pull them out, and strong feet to hold on to stems while feeding. It also loves Monarda (Bee Balm) seed heads, so it's good to leave those up too. Be lazy with your seed forming plants, and you'll have more birds visiting.