I move a lot. Can't tell you why -- bad luck, maybe, or a naturally nomadic disposition. Either way, when I do pick up roots, I think very carefully about where I'm about to plunk them down again, and one of my A#1 considerations is walkability. Not because I hate my car, or am trying to debunk the nobody-walks-in-LA myth single-handedly, but because being able to walk to grab coffee or dinner or see a movie rather than spending an equivalent amount of time driving to do those things just make me feel good, like I'm interacting with my community on some basic level -- or that I have a community to interact with.
In any case, I wish walkscore.com had existed last time I moved -- it would've made things a heckuva lot easier. It's a particularly useful Google Maps mashup, which looks at how far away nearby stores, restaurants, schools etc are from your address, and gives your house a walkability rating. My current place got a pretty sweet 89 out of 100: very walkable. The uber-suburban house where I grew up, on the other hand, got a seriously lousy 14: you definitely need a car. I find walkability to be a close cousin to liveability, and walkscore an uncannily accurate barometer of both. How walkable is your house? Do you agree with your score?