I'm young so i guess it doesn't really count yet, but I still do all my trips by bicycle, including riding to uni 10km each way instead of the bus. That 55 bucks a month I save goes a long way on my 300 dollar a month budget. In fact, with that saving I'm taking the opportunity to start up saxophone, as the hire for the saxophone is also 55 dollars a month.
It also will give me exercise for the whole tertiary year. Here in Australia, theres always a campaign going on, about doing 1 hour of exercise a day. Well going by bike not only saves me money to spend on my hobbies, but it gives that recommended dose with much less effort than it would take to drag myself to the gym. Also it gives me that needed wake up call before my 8o'clock lecture.
It is so common for people to live less than 10 km away from their workplace or educational facility. Such trips are the perfect start and end to a day. You get a good workout, but you don't get completely buggered. It takes only half an hour each way, and you don't have to shower or wear special clothes (debatable but seriously, you're going to work or study -- you're not going to a ball or party -- you're gonna get sweaty and theres nothing wrong with some natural aroma anyway).
On the other hand, I face-planted on my commute today, I guess thats not a risk of driving or busing to work. It was right in the uni, when my textbook swung over and locked my front wheel. Don't worry the bike only suffered minor injuries. I was alright as well. But the physics textbook was pretty battered. Maybe if I read that text book a bit harder, I'd know that bags swinging close to a front wheel don't lean when you lean your bike.