Color Themes?

I have to admit that it's completely new to me that a wedding needs a "color theme". Obviously white is not good enough for this day.  However, it seems that things are risking not being cohesive if the color theme is not decided early enough.  I probably will really go with WHITE.  As far as I know, the reception place is filled with orange-yellow color.  That makes thing slightly harder.. What goes with Orange??? Well.. more specifically - 0xff9900.

First thought is purple and then white.  I guess Tiffany blue is out of the picture (It's a little be tacky nowadays.)  However, it's summer, some red/pink/yellow would be nice too!
More research to be done...