Well...how else do you start a thread on shrubberies?
When I first started building my tropical forest, one of the first steps was to plant a perimeter of Viburnum Odoratissimum. I have about 350 feet of hedgeline, planted about 5 feet apart. That's a shocking $1000 worth of 3 gallon pots of Viburnum, and for the most part they've done a good job of filling in and blocking the neighbors and highway noise. The only problems in the past 3 or 4 years are:
I've had a few random