A scooter is good for a single person who doesn't mind being a pop bumper target for anyone in a bad mood, but doesn't work for most people in most places.
As for changing cars, sure there is expense involved, but you're not taking a few things into consideration.
1) I'm not going to be paying for unscheduled maintenance on this car until 2010, when the bumper to bumper warranty expires. This is the real reason we made the switch, to eliminate the headache of a pain in the ass car. Gas was a secondary reason.
2) Gas is $2.25 now. Last year gas was $1.60. The year before that it was $1.25. At this rate, we're looking at $3 this year, possibly $4 next year, and on from there. The rate of savings, though not that huge right now, will increase dramatically in a short amount of time. The vehicle switch will save a good amount but it's the shortened commute that is already saving $150/month even if you don't factor in the price increases.
It really comes down to doing what you can do when you can do it. I was able to make those adjustments because it was time to make changes anyway... coincedental, yes, but improvements for sure.