I remember from a very old Martha Stewart, like 20 years ago, a wedding dress article about sweaters with satin skirts for a winter wedding dress alternative and they had a wall lined with fur trees, and maybe they had white lights but maybe they didn't, it was very simple and pretty.

then I went to her site and found:

http://www.marthastewart.com/article/white-christmas-let-the-party-begin?autonomy_kw=christmas%20wedding&rsc=header_38

I think pine branch garlands, and trees and flowers in white, silver, green (trees) and gold would be warm and pretty and not the usual green and red.  I searched for christmas and wedding and lots of white christmas themes came up.

oh they also had a mistletoe kissing ball which was fun

For your guest tables you can always use wreaths on the tables decorated with the colors of the wedding.  In the center you can place a hurricane in the center, a tall vase filled with Christmas balls, or a low bowl with water and floating candles.  The wreaths can always be given away.  Very simple and effective.  If you are doing long tables you can always use garlands down the table decorated in a  serpentine shape with lots of elevated candles.  This is always good for down a feasting table or a head table.  If you do it in artificial you can always use it at home around a door way, over a picture or on the mantel.  One nice thing is you can use the artificial items from year to year and it will remind you of your wedding day each year you decorate your home.  I have also found that your discount store are carrying more and more decorator colors in ornaments and ribbons now and these places are not only good resources, but are very reasonably priced.  I do a party for a local client every year on a budget and you can get a big bang for your buck.  Visit my site at http://www.appleblossomstampa.com for some inspirations.

Good Luck

Scott