There really isn't any room for growth here. I live in a town of about 25,000 that does have 2 town centers. I live just a bit too far to walk there quickly (just under 4 miles), but it is perfect for a bike trip/errands. We have lots of protected conservation land and people generally go nuts and protest any new growth or change.
What bugs me is they are protesting even some of the "smart" growth ideas that CC mentioned, such as smaller homes/townhomes in closer proximity to each other. These are people who are supposedly into "the environment," but they really want to keep their suburban-semi rural environment the way it is. Since moving to MA, we have lived in 2 other towns that were decidedly more rural. Neither had a town center and it was 6-7 miles to a grocery store. The first town did have shopping on the edge of town, that bordered a large mall/shopping area in Nashua, NH. It brought a lot of $ into the town from taxes, but caused congestion.
Generally, towns here that have some type of central shopping area and might be bikeable/walkable are expensive and don't have a variety of housing. And I agree with Deb. Bike commuting was awesome for me when it was 6.7 miles. When it became 13.5 miles, I did it, but it was less enjoyable and required more planning. I am hoping to find a commutable job when I graduate in 2011, but it is not going to be the deciding factor.