Big and tall

I'm still noodling around about the sunny section of the front lawn. I'd like something big (yes, I know Mom recommended a low bed but I'm considering something else for the section closer to the house, to screen my neighbors' driveway). Maybe start with some big annuals to see if I like the look and then go from there?
Like Mexican sunflower (Tithonia rotundifolia) and other tall things?
In the meantime, Margaret Roach recommends these tall, easy perennials for screening.