Wedding dress accessories?

I'm getting married in las vegas on december 20. My fiance and I are getting married in a gazebo at dusk, at the famous little white chapel. I'm going to be in a black evening dress by j.crew (link to see the dress below). Its strapless, fitted to the natural waist, and flared at the bottom. VERY audrey hepburn-breakfast at tiffanys. I loved it. I'm a dead ringer for audrey....so, I had to get the dress. I'm planning on wearing very high strappy stilletos and a pearl choker. The only thing I'm frazzled about is the hair?! I have shoulder length, slightly layered dark brown hair. Should I wear it up to show off a $50,000 choker or, because its strapless, would the hair look better down? And cream roses or red? Below is the link to the dress
http://www.jcrew.com/catalog/product.jhtml? id=prod71858651&catId=cat80126

Not sure what the convention is...but my wife wore her hair up for her wedding (she usually wears it down).

>cream roses or red?

For a black dress, it might look too much like a funeral or something, and not like a wedding, if you were holding red roses - so my suggestion there would be cream.

Congrats on the engagement / wedding, wish you the best of luck.