culvers root (veronicastrum virginicum)
foam flower (tiarella cordifolia)

I really like old fashioned 4 o'clocks. They open in the evening and stay open through the night. They attract hummingbird moths which are a cool sight to behold. Four o'clocks come in a varity of colors.The link below shows a picture of some. Four o'clocks are a great background plant, they grow to look like a medium sized bush full of lovely flowers.

http://www.humeseeds.com/fouro.htm

Datura smell wonderful at night and in
the early morning. Also butterfly ginger
is white and smells good!

Silvery (fragrant) lavender and artemesia will give you more silver foliage. 'Pinks' (Dianthus) smell like clove and come in colors ranging from white to pink to reds and some varieties have blueish-grey foliage. I've grown fringed white ones from seed. There are varieties of thymes with silver or golden foliage too. Consider other fragrant shrubs like mock orange (some varieties like 'Innocence' has variegated foliage for interest when not in bloom), and Korean spice viburnum carlesii. For fall interest I grow white wood asters and white japanese anemones, though these aren't fragrant, and white phlox carolina blooms summer through early fall.

Don't forget white sage, by moonlight they would look silvery. It's how I got my daughter's middle name Silversage.

These are some of the other plants I have in my moon garden:

August Beauty gardenia - tree form
butterfly ginger
Casa Blanca lily
David white garden phlox
Milk and Wine lily (crinum x herbertii) - a very old variety from my great-grandmother's garden
Thalia narcissus
Snowdrops
John F. Kennedy rose
Dusty Miller (Senecio cineraria) - grows perenially for me in z7
Fragrant Angel echinacea
The Pearl tuberose
Peruvian daffodil - supposedly hardy only to z8, but mine have come back for 3 years now in z7