The recent plans for metropolitan Paris include many interesting ideas for using trains to integrate outlying neighborhoods into the city. They also helped change my perspective on urban transportation.I've always favored streetcars, trains, and subways. Maybe it's the poetic qualities alluded to by Mario, or that they move so many people efficiently, with fewer negative ecological impacts than gas-powered autos. It's also nice to be able to relax on the way to work instead of negotiating rush hour traffic.
However, trains aren't available in many areas and new systems require massive political and economic backing. While I agree with Burnham, Brendan, and others who encourage planners to think expansively, small changes can generate momentum behind larger changes. When it comes to public transit, we might start with the city bus.
Buses generally lack the poetry of railways. This may be why there hasn't been a Bus Named Desire or a Soul Bus. I tend to associate buses with congestion, exhaust, delays, noise, and advertisements. They kind of look like giant loaves of Wonderbread. These impressions aren't necessarily justified, but I think they're fairly common. At the same time, bus systems are less expensive and more flexible than trains. If we can make them more appealing, they might become a popular alternative to private vehicles.
Improvements to buses can take many forms. Assuring that they're ecologically friendly is essential, and may be less prohibitive than laying new train tracks in dense urban settings. As for delays, programmed traffic lights and dedicated lanes might allow buses to pass quickly through congested streets. There could also be smaller buses with more frequent and extensive routes. Comfort should be a top priority, along with wireless Internet, as found on Google's buses. Great artists and designers could be commissioned to turn buses into beautiful parts of the urban environment, like the vintage streetcars of San Francisco.
Compared with the rail projects proposed for metropolitan Paris, improving buses can be accomplished swiftly by local government. So why not make them as efficient as trains, comfortable on the inside, and attractive on the outside? This may help reinvigorate public transportation and lead to more expansive change. 
(Photo credits: Green Bus to Green Acres by Frank H. Jump; San Francisco streetcars by Will aims to rage; Corgi 1:50 scale Green Bus from JB Diecast)
