Check out this totally cool site that maps housing plus transportation costs (plus a whole bunch of other statistics, like average block size) by census block group. They use census data to estimate the average home and transporation costs as a percentage of median income. The map's creators' point is that those suburban homes are a whole lot more expensive when you factor in transportation costs.
I'm fuzzy on their methodology for estimating transportation costs. I spot-checked the block groups around my neighborhood, and found big differences in transportation costs that I'm skeptical exist. And bear in mind that housing + transportation costs may take a huge bite out of, say, a Pflugerville household's income, but they would probably be a mere nibble compared to the bite of a central Austin mortgage payment.
Still, this is the coolest thing I've seen in a while. (I admit that I probably have a warped sense of "cool.")
