I think you have a lot more choices there than I do here in Nebraska, but I started with Datura, or Moon flower bush. Also moon flower vine, white phlox. I want ginger lillies and night-blooming jasmine, but I might be too far north.

This is the moon garden we started last fall, 2009, and the 150 white tulips (early, middle, and late) in the shape of a crescent moon.

The other plants you can see are Shasta daisies, which grew too tall, as did white feverfew. I did plant datura, but didn't like it much.

Next year, short, showy white flowers!! white geraniums, Snowman marigolds, and white petunias.

I go with the gray a lot - dusty millers, etc. They glow and they're hardy, too. White glads planted every 2 weeks give a punch and yes, white petunias and marigolds are a must.
The shorter dwarf variety of pampas grass gives a good white, too.

I love the white annual vincas, either solid white or with a pink or red eye. They line a pathway nicely, some come back the following year if the winter is not too bad. And I like the chartreuse ornamental sweet potato as well. They are close to white, being so reflective, and they make purple tubers that can come back the following year as well. They would work well in bright sun, of course.

And then I also love the white star jasmine as a sweet smelling vine that is ever green down here in AL.

Lambs ear is another nice gray-leafed plant with small pink blossoms. And you can also get hold of some aztec grass which is like leriope and monkey grass, but is paler green/white striped like a spider plant. They also have a really fine variegated ajuga reptans which is pale green/white leafed, ground cover and has spikes of pink or blue fuzzy flowers. Getting a spot of variegated ginger is also a good idea, or maybe some of the hardy aspedistra, cast iron plants, which love shade, can take dryness, and come in striped green/white long leaves. I LOVE these tough customers, and have planted many of them at the back of my flower beds. For spring, look for the wild white violets and pull them out of the lawn and into your low borders. They don't last long, but they are fine for the time they bloom. And then don't forget the variegated hostas, I have learned to love them up north, and now am pleased that there are some varieties taking a little more heat as long as we give them shade.

Oh yes, if you can get some of the green/white caladium bulbs, they will brighten up a row of small boxwood under a big shady oak tree, they don't like too much sun. And just like narcissus, the critters love to eat the bulbs. sigh...
what we must go through to keep a variety in the gardens!