Gardening and Horticulture - A Border for Privacy

I've been looking for a while for an evergreen tree/shrub/bush that will provide a screen for the property line of my back yard (especially in winter). My lot size is 1/2 acre and borders the neighbor behind me. Beyond the neighbor is a somewhat busy street which I would like to block for aesthetic and noise reasons. My dilemma involves size restrictions. The backyard slopes down, so a simple fence or hedge would be too short, and power lines along the lot line limit the height to about 20 feet.

I live in Milwaukee, WI along the coast of Lake Michigan which is located in zone 5 (because of the lake), but would like to find something hardy to at least zone 4. The soil is moist and leans toward clay, but is enriched with organic matter and will probably be boarding a vegetable garden which may provide some nutrient run off.

Arborvitaes seem to be what I am limited to. I would appreciate any and all suggestions on this matter!

Some hollies range in the 8 to 15 foot size and are evergreen.

Contact your local Dept. of Agriculture Extension Agent for a list of plants that meet your needs and specifications that will do well in your Zone. You will need to know spacing requirements. Too, you want something that tends to be disease resistant and require minimal maintenance.

Near arborvitae but a bit healthier in that weather would be the over used but pretty Leyland Cypress ... tall and elegant and a fairly fast grower. Some 20' plus at maturity, I think?