It just occurred to me that in my description of clothing in earlier posts I never got around to talking about helmets or gloves. I consider both necessary safety equipment. I'm especially a helmet advocate as back in college I had a good friend who was a Cat III road rider, a truly gifted athlete who on his way to visit a friend hit a patch of sand and went down hard, hitting his head on the pavement. He wound up in the hospital for weeks with right side paralysis and had to go through years of therapy. He never rode a bike again. So naturally, I'm never without my "brain bucket." when out in traffic or when the risk of falling is high. My one exception is whenI'm very very close to home (I.E. test riding immediately in front of the house) or I know the roads I'll be on very very well and there is absolutely no traffic at all (think residential street).
The main criteria is to make sure the helmet is SNELL certified other than that let you budget and conscenice be your guide. As of late I've been partial to Specialized helmets. The current one I've had since '98 (Yeah, I know it's over the 4 year rule) is an "Air Cut" in black. Which raises the next subject.. Color. Black is good in foggy conditions, but lousy in the dark. It's also lousy in bright sunlight as it absorbs heat directly from the sun. White is pretty good at night and in bright sunlight, but is terrible in foggy or snowy conditions. Red depending on the shade is okay in fog, but not terrific. Heatwise it's a little better than black. If you do most of you commuting at night or before the sun comes up my vote is for either white, Neon Yellow, or Red. (I'd include blaze/hunter's orange, but my experiences with this color have not been happy ones)
Road helmets are good, if you primarily a racer, but I've found mountian bike, sport or "enthusiast" helmets to be more practical. The usually have a clip on visor
. I've found that the visor is very helpful for holding on a head lamp or battery powered miners lamp.
Gloves.. I'm old school. By far I've found Performances' crochet gloves are the best, but in times past when I could get them I'd also wear Rhode gear gloves; however, I believe Rhode Gear is out of the glove buisness . These are also a matter of taste, but you definately want a pair of you go down. Lacerated palms are pretty painful while they are healing.