How do parlor-walls show what is valued in Montag's society?
The actual content of the parlor-wall programs tells us something about social values, but the fact and nature of their existence is much more informative.
The programs that Mildred, Montag's wife, seems to build her life around are, generally speaking, vapid and meaningless. It's pretty clear that Bradbury's intention is to portray them as obnoxious and annoying, and that Montag doesn't really see the value in them, at least not to the degree that Mildred does. To this end, the programs represent what Faber mentions during their meeting; that despite the abundance of "leisure" time in this society, that time is occupied with unthinking entertainment, and that entertainment is so loud and pervasive that it is impossible to compete with.
This ties into the nature of the parlor-walls, being that they are essentially full-wall televisions. Not only is there an element of social prestige in them, as indicated by Mildred mentioning that they should have a fourth wall put in, and that it's "only" a third of Montag's yearly salary. This represents how the consumerist elements of this society have insinuated themselves into people's lives on an unprecedented level; aside from Mildred's disregard for the financial considerations, the home itself is being transformed into a television, and Mildred is coming progressively closer to living inside her programs.