Never taken a flu shot. Never will. I strongly believe that a decent diet and regular exercise is a big key instaving off common viral infections. Good hygiene during this time of the year such as constantly washing your hands also helps. The one year I did get a flu shot, I picked up the Norwalk Virus. That was no friggin picnic. Thing is, while other people I knew who picked up were sick for days, I recovered within 24 hours.
I like to keep my body as clean as possible, drink 3-4 liters of water a day and prefer to let it do its natural job and fight off most infections without any drugs or antibiotics. Drug and Pharmacutical companies are making a killing off of our society's need for a quick fix. Cough medicines don't do squat for a cold, and in fact in most cases, slow down your bodies ability to recover quickly. They dope you up so you can pass out. EVentually, your body adapts to them anyways, and they stop working. I used to for a time take NyQuil whenever I got a cold, except one year a while ago, I found out it just wasn't working anymore. You'd be better off taking a sugar pills or something.
I also under dress during the winter months to help my body aclimate to the colder temps. Most of the winter I wear a warm thick hoodie w/ long sleeves underneath. I only dress warmly when the mercury really drops. I think the worse thing you can do is get all bundled up, hop in your car drive for an hour, sweat, then get back out in the freezing temps all soaked. It causes your body to go into a type of shock. I rather stay comfortably cool then over heat anyday.
Sorry for the speach. My 2 cents, take it or leave it.