Whether you're defending yourself from barbarian hordes or you just want a little privacy from Joe the neighbor, here are some ideas for privacy in the garden that won't take hundreds of years to build or grow.
Vines. It's easy to be creative with vines and if you find the right ones, they can grow fast and hide your white, white legs from your neighbors. They will need support-depending on your budget and taste. Trellises, arbors, posts with twine; you get the picture. You'll need to make sure that your structure is stable enough to support your vine when it's mature. Steer away from roses and wisteria and consider vines with great foliage-the thicker the leaves the better the privacy. Climbing hydrangeas are some of my favorite and while not the fastest, they're worth it when they mature. Some take full sun.
Screens. Buy a moveable screen and fill in a gap as your privacy plants mature. Make sure you do this artfully so it blends in and doesn't look like it fell from space.
Create a secret pocket. Grow an L-shaped stand of Nandina in a corner-or create a corner. They will grow to create enough privacy but they'll still let some air into your secret garden space.
Big containers. As you wait for the photinia hedge to mature consider planting some quick-growing bamboo or other fast growing grasses. When your hedge matures you can move the containers to a new spot. Make sure you educate yourself on bamboo if you decide to put it in the ground-you may end up with nothing but bamboo in a few years. I usually recommend keeping them under control by keeping them contained.
Go Japanese. Visit your local Japanese garden and study it with an eye for privacy elements, corners, quiet areas. Japanese gardening employs subtle ways of achieving a goal and these can translate quite nicely into your backyard if done well. You don't need to build a fifteen foot expensive wall when a few properly placed plants and some tall thin wood panels would do...