As for helmet ventilation........Suomey and Arai are at the top of the scale as per helmet testing that I've read. They are also expensive and noisy. If you want great ventilation, you will get noise from any helmet. The helmet must be in the air stream in order to creat a low pressure area behind the helmet. That's how they draw air through them. The faster you go....the better they vent.I have both an Arai and Suomey full face and can say they do vent very good. I also use an Arai open face that vents very good. I can really tell a difference when the vents are not open on a hot day. The HJC full face is suppose to vent pretty good for that lower price range. Research the web sites for evaluations on the helmets they carry. HelmetHarbor.com and SportBikeTrackGear.com have good review systems with vedios.In order to get the best ventilation, your windsheild will have to be at the correct height to place the vents in the air stream. Unfortunatley you'll proably get some buffeting from this. You can experiment with the shield height to get the best compromise between buffeting and venting. I find that placing the shield so I'm just looking over the top of it to be the best for me. As for my choice........I choose to wear a helmet all the time. I've been on the pavement three times and EVERYTIME I've hit my head hard enough to cause damage if I had not been wearing a helmet. I was even knocked out after a dirt bike crash once and I was wearing a helmet then. I've seen others go down and not hit their heads. Every wreck is different. I feel it's just a matter of time and luck, as to if and when you will go down. You can be the most defensive rider out there, but if some doofus screws up, will you be dressed for the event when it happens? I respect the right for everyone to make their own choice because I don't want the government telling me what to do. But as far as I'm concerned, no one has ever had to tell me to wear a helmet or a seat belt for that matter. They both are life savers.
In addition to what Morgan posted, if the helmet fits properly it will afford the wearer much better protection from an impact than one which is too loose. I'm a big fan of the modular helmets; I have some old full-face helmets that were great when I could wear them, but now that I'm an old, broke-down bespactacled fogey, I need a helmet I can use with glasses. I'm not trading in my ultra-lightweight specs for a set I can put on through a full-face helmet. I sometimes wear a 3/4 helmet with a flipup shield when it's hot, but if the weather's cool I wear the modular. I've heard several people say they won't wear a modular because the chin bar isn't as strong as the chin bar on a full-face. I'm sure it's not, but if it fails I'm no worse off than if I wore the 3/4 helmet. And even if it does fail, it may well still provide SOME protection to my face, especially if I'm sliding merrily along the pavement. As ugly as I am, I just couldn't justify spending money to reconstruct my face.Protective gear is a choice (at least for now, there's talk of making helmets mandatory again), and I often ride without armor. But losing some hide won't make me a vegetable, and I always wear a helmet. There are a lot of bikers who seem not to have a brain; I believe they are why helmets are optional -- they won't be hurt by head trauma even without a helmet. For those of you with a brain, consider that motorcycle accidents are on the rise, and the increase is partially attributable to the don'tgiveashit attitude of the contemporary American driver who believes that he/she is perfectly capable of operating a 5,000 lb. killing machine at 85mph while texting, eating, applying makeup, yakking on a cell phone, and yes, even changing clothes (I've seen it myself). While every one of us who has a driver's license knows (or SHOULD know) that two seconds is the minimum safe reactionary gap, the average driver around here follows at less than a one second gap. American drivers get more dangerous every day. Protect yourself.
Just got back from my Colorado ride last week. While I was there this happened just outside of town.http://www.ouraynews.com/Articles-i-2008-07-25-182297.112113_Motorbike_passenger_killed_in_crash.htmlRW