Thanks for writing. There are several varieties of columnar juniper (such as 'Blue Arrow' or 'Wichita Blue') that grow tall and upright but stay very narrow (the narrowest ones only get 3 feet wide or so). You could plant them irregularly to help them feel more natural and less like a wall, especially if you leave a few gaps in between the plants.
If you want something taller, there are columnar varieties of several pines and spruces (including blue spruce). Ask for them at your local garden center.
---Justin, Senior Garden Editor, BHG.com