I had a fabulous bike-to-work-day last week. I even recruited another co-worker for the event. We also had a guy that ran to work since he didn't have a bike. Interestingly enough, it was the young folks in the office that were excited about the prospect; the middle-aged people wanted nothing to do with it. One of my dear co-workers said: I have a prius now, I don't need to worry about biking to work! Oh dear.
Most of my bike route is along the Santa Ana River which is nice because it’s a well-paved path, kind of an equivalent to the Burke Gilman Trail in Seattle.
Unfortunately, the last mile in on a busy street that is seriously lacking in the sidewalk and/or bike path department. It’s a bit of a nightmare. 
At this point, that last mile is the only thing holding me back from biking on a regular basis. Part of that is because Chris and I saw a bizarre bike and car accident while in San Francisco. We were eating breakfast outside at a sidewalk café when we heard a big crash. A man and his bicycle were sprawled in the middle of Market Street, perhaps one of SF’s busiest streets, during morning rush hour. Evidently, a woman getting out of her cab had opened the door directly in front of the cyclist. He went flying over the handlebars after colliding with the door. The door of the cab was completely broken. Thankfully, the cyclist wasn’t seriously hurt. Events like that always reside in the back of my brain though when I’m bicycling through heavy traffic.
I think it’s completely understandable for bicyclist’s to be wary of inattentive drivers because the bicyclist will always lose, no matter who is at fault. I had a coworker once that regularly kicked out people’s tail lights because he used to get so pissed off at people driving him off the road. Actually, (on a totally unrelated note), that co-worker had an article in the Seattle Times that can be found here.
