Chocolate brown is going "out" and eggplant is in for 2010 as a dark bridesmaid color. Monochromatic palettes are big (think eggplant, purple, lavender, white.)
I'm also seeing a lot of elegant palettes like ivory, white, blush pink and gold.
Grey is also huge right now as a neutral.
Crisp green, white and black are also big and eye catching to today's bride, but I think this trend is on it's way out. (Think greens in flowers, not actual greenery).
Then there are always the really fun eye catching palettes, which is what I would do at a show. Pick a color combo that you don't see anywhere and create your own look.
It also depends where you are and what bride you want to attract. If you are not in a major metro area, your trends may be a little behind.
If you want to attract a modern and fashionable bride, always follow what is hot in the fashion world. If you want to attract the everyday bride, stick to the less risky palettes.
Oh, and orchids, peonies, garden roses and anything out of the norm are big.