I spent my middle and high school years in Athens, GA. It would not ordinarily be seen as a target for sprawl-bashing, given its ostensibly compact nature. And it's true, the downtown and campus are fused into something fairly livable.
However, as usual, 90% of the population doesn't live in that tiny core, but instead in the same kind of low-density layout one can find anywhere in America. While I haven't been to Ann Arbor since grade six or so, my recollection is that it's similar; wonderful UMich campus, nice downtown, but most of the Ann Arbor-Ypsilanti area? Same old automobile folk traditions. Am I misremembering?
Re: comparing density --
Density is certainly not the only variable. In my article, I made the point about how proximity/adjacency != walking accessibility. That seems relevant, too. It's probably quite possible to build a place with a decently high density where a car is still required to go anywhere, or a relatively low-density but profoundly pedestrian-friendly hamlet.