Answer: Your selection is going to depend on the growing conditions (sun, shade, moisture, soil type, wind exposure) where this will be planted, as well as the amount of space you have available for the plant to mature, the height you have in mind, and whether or not you need a more formal look or a more relaxed look.
Most evergreens are slow growing, however columnar arborvitaes are often a good choice for screening. Deciduous plants tend to grow more quickly, some very quickly. Forsythia for instance can grow to ten feet tall and will make an effective screen year round due to its dense twigginess, but it needs a space at least eight to ten feet wide if left untrimmed. Both of these need full sun to grow their best.
Your local professionally trained nursery staff should be able to help you analyze the growing conditions where you want to plant and identify plants that would thrive there, then you can make your selection from those based on your design preferences.
I might also mention that an island shrub planting closer to the spot you want to protect from view can sometimes be equally if not more effective than a hedge style screening. That might be an option to consider.
Good luck with your planting!
Q&A Library Searching Tips