I wore no helmet when I lived in Beijing. I would tear down those streets faster than most taxis with impunity, but now i'm back in australia (for however short a time) I have nothing against wearing a helmet.

I always wear a helmet. My parents were neurotic about it when I was a kid, and I was studying i na medschool (not medecine, Biochemistry, but our lectures/labs were in a med school) and some of the head injuries I've seen there make me sick to this day (90% of which would have been survivable had the rider been wearing a helmet - the one poor lad whose head went under a bus wheel didn't stand a chance, helmet or no).

Plus I got thrown from my bike once - was clocking about 30mph down a hill and a car pulled out of a side-road right in front of me - literally, I was about 2m away. My brakes slowed me down a little, but I still hit the car and got flipped over the handlebars (and my bike made a massive dent in the bonnet of the mercedes, hehe). helmet cracked clean in half, and I had a bit of a concussion, but it meant I wasn't being scraped up by the paramedics/coppers.

Always wear one when enjoying a bit of Downhill Mountain biking, or going across the Treetops path in Wales, just because I'm not that good and tend to fall off a lot.

Mind you, I've got one of those quite funky mountain-biking helmets, the onces that are like racing helmets but less curved and with a little mudguard/visor/sunshade thingy on the front, so I don't mind getting seen in it. A bit like fix-the-spade's but in silver & red, and slightly more sleek (not so bulky vertically).

Oh, I thought you were talking about motorcycles... i freaked when I saw most people said no.

I don't wear a helmet while riding my bike simply because it's a bicycle, It's not like I'm going 60MPH down a highway.

BTW, Bike means Bicycle, who would call a motorcycle a bike?

MaxMees:
Safety first, or respect of your peers? Not obvious respect, but they subconsciously respect you.
Me, I don't wear a helmet and I ride to school nearly every day, I've had a few spills but no injuries whatsoever, but then again, I always ride with at least a small bit of awareness and common sense.
So what about you guys/girls?

Part of being young is thinking you are invulnerable, but let me tell you a cautionary tale.

My wife has a younger sister, who around 2 years ago moved to an idyllic, quiet island in the Pacific Ocean, very few cars, almost everyone rides bikes around.

She wasn't wearing a helmet while riding a pushbike one day, and hit a small hole in the road, and went forward over the handlebars, striking the side of her head on the ground.

She was knocked unconcious, and was out for around 30 minutes. In addition, she hit her head so hard, she ruptured an eardrum.

Her injuries were so severe, she was airlifted back to New Zealand via a medical air ambulance, with a cost approaching US$50,000.

Rehab so far has taken over a year, during which she couldn't focus for long periods of time, preventing her working (as a successful photographer), requiring an awful lot of sleep, and completely disrupting her life.

Nonetheless, she has recovered better than any doctors predicted she ever would.

The point is that NOT wearing a helmet, with all the information and research available, is stupid, and if you don't wear a helmet, you're an idiot, and completely disinterested in how your actions will affect your family and others around you. Common sense cannot EVER be mentioned in the same sentence as not wearing a safety helmet on a bike.

If your friends give you grief about it, get better friends.

I always wear a helmet,
But then again I wouldn't consider us in the same catagory of rider, I do alot of bmxing and cross country riding, and concusion stop being fun after the 3rd one.

Wear a helmet snowboarding as well.

It's kind of a funny story why I don't. See, I had just put a new tire on my bike with the help of my dad. I was putting my bike away and my dad backed his truck out for whatever reason. There was a loud crunch and I realized that he had run over the helmet, crushing it completely and making it useles.
And I never got a new one.