I've been so busy at work this week I haven't been able to get to this thread. I agree with all that you're all saying about mass transit and hybrids--I think any or all of the above work. Also, though, I think that for those of us who do live close enough to work, getting there on your own power is a nice eco-friendly option that won't use any of the hidden costs of auto or public transportation. I live 4 miles from work, and in nice weather (like last week, but now it's been raining this week) I ride my bike. I think if more people did that, weather and distance permitting of course, then we wouldn't need as much of either of the other two options, and the daily commute would be a lot less frustrating.
Of course, there's the question of how much you can carry on a bike. I like to take my laptop to work and write, and I don't like to chance taking it on my bike. So there are complications. But it is a good thing for my body, getting the exercise, and a good thing for the environment, in that I don't own a car anymore. (And a good thing for my budget, in that I don't have to pay for gas, car payments, insurance, etc.)
All the trains and trolleys here in Boston are electric, and many of the buses.