Pitman, you're correct about the high-hp pumps and large filters. There normally isn't any reason to get a big pump, unless someone has a spa or water features that require a lot of water flow. It costs more to buy, costs more to run, and doesn't provide any benefit over a smaller pump. You do have to run it longer, but it costs less to run per volume of water moved.
That being said, some people with long pools (like 20x40') with only one return at one end have found that a small pump won't circulate the water at the far end, but that won't be an issue with your round pool.