I've heard Elderberry referenced in a million places as the best holistic cure for colds, coughs, sinus, etc. Here's a little more info about it from http://www.herbwisdom.com/herb-elderberry.html.
Elderberries have been a folk remedy for centuries in North America, Europe, Western Asia, and North Africa, hence the medicinal benefits of elderberries are being investigated and rediscovered. Elderberry is used for its antioxidant activity, to lower cholesterol, to improve vision, to boost the immune system, to improve heart health and for coughs, colds, flu, bacterial and viral infections and tonsilitis. Bioflavonoids and other proteins in the juice destroy the ability of cold and flu viruses to infect a cell. People with the flu who took elderberry juice reported less severe symptoms and felt better much faster than those who did not. Elderberry juice was used to treat a flu epidemic in Panama in 1995.
I cannot recommend Elderberry strongly enough! I like it because it doesn't taste bad (I add it to my tea or juice and don't even notice it) and because it doesn't make me have weird "medicine head." I'm really sensitive to medication so any type of cold medicine makes me pretty wacky. And any medication with a "D" attached to the end of it is the worst. D = dumb dumb in my world because that's what I turn into if I take it.
Side note: When I was researching Elderberry, I found The Elderberry School of Botanical Medicine which has an Herbalist Training Program. And it's in Portland! I'm going to add this to my "when I grow up, I wanna be..." list.