Most of the time house "affordability" is articulated as "drive 'til you qualify." Affordable housing is centrifugally located on the suburban periphery, most often far from employment centers.
A new database adds in transportation costs to housing costs to arrive at a "true" home cost.
I don't really know how new this data might be - I haven't explored it much - but the interface is certainly easier than the clunky census thingy I've struggled with.
If you compare this map of "buildable land" you'll notice it overlaps a lot with the most expensive housing+transportation land!
Maybe there are some data wizards out there who can overlay the urban growth boundary?
There are lots of other queries and data overlays, so play with it and if you see something especially interesting drop a comment!