Today was my 50th day of biking to work since June 25 of this year. This month, I have only driven four days (one being the first day of a new job, two on days when I needed to be able to get around more quickly to deal with furnace problems, and the last being due to unexpected cold and strong winds).
The goal for 2009 will is to break 200 days, which averages out to less than four days a week (261 working days in a year). This will be far easier than before, as I am less than five miles from home by bike rather than more than 16. My last fillup was a full four weeks after the prior one. That will increase for the winter with driving up for skiing, but my gas usage for commuting to work has decreased to nearly nothing.