I would choose one of the H. paniculata varieties. I've read that 'White Diamond' stays white for longer than most, though I have no personal experience with it, and Tardiva, because it blooms later, is more likely to stay white. The Swan (AKA 'Barbara') has really large white blossoms. By now my Annabelle is pale green, though it has a long white bloom, and I am not fond of the tannish-pink that Limelight turns as it ages.

I have done this with my yard. I only want white flowering shrubs and perrenials in the front yard. I replaced a hedge with white Encore Autumn Angel Azaleas and am planning a hedge between our neighbors of Limelights. Same situation with both driveways. I have a pretty wide side yard so I am *planning* an evergreen Japanese Ilex hedge behind that. We'll see. :)

There is a wonderful thread here Re: Limelight hedges. A member updates the post every year. It's stunning!

http://forums.gardenweb.com/discussions/1992345/how-are-those-limelight-hedges-looking-pic?n=47

The answer may depend on a few things like the amount of sun, width of the space and whether you'd like to block any views. I have Incrediballs, Limelights and a few Little Limes in my front yard. The Limelights are mostly toward the outside edges, including a row on the far side of my driveway between one neighbor's house and mine.

I like the Limelights a lot, and I also think having them there improves the neighbors' view. Their house is on an angle that means it somewhat overlooks my driveway, but now they have Limelights to look at instead.

How about a pic of the spot and some measurements. Limelights get huge over time, and others may not take full sun. More info would be helpful.