If there's one topic that's guaranteed to come up in every casual conversation in the San Francisco Bay Area, it's the cost of housing. I assume that most people are aware that rental rates in and around SF are crazy. But just in case, the median monthly rent for a one-bedroom apartment in the city is somewhere around $3,450. At such a price, a net salary of $41,400, wouldn't leave you a single cent with which to eat.
It's easy to compare this rental rate to that of other cities and gasp in horror. However, such aggregate comparisons can be misleading as what you'd really like to know is not the relative median prices, but rather the relative cost of similar apartments in different cities. I suspect that the median apartment quality in SF is lower than that of many other cities.
As a personal example, we recently moved into a ~$2,000/mo complex in SF's suburbs. Upon taking occupancy of the unit, we discovered that it didn't have a working phone line. This had to be repaired by AT&T technicians who noted that the wiring in the unit was terrible, leading to crossed wires and shorts (hence three weeks sans internet). This is important, because you generally don't test the wiring of places during the open-house tour. It boggles the mind: what is being done with these rents? It's clearly not upkeep.
Another of my suspicions is that part of the reason that rental prices are being driven up is because most techies are young and don't mind essentially lighting a large fraction of their salaries on fire rather than investing it in a house or condo . On the other hand, if you're a couple of thirty-somethings who just started a family, investing in a home is the kind of thing you start to think about. For kicks I took a look at some places nearby. Crappy homes start at about $1,000,000 and go up from there. After putting a downpayment on something like that, I'd be pretty worried about a potential drop in housing prices.
At some point, our son is going to need his own room and even maybe some space to play. Someday we're going to want to send him to a decent school, which usually involves living in the right area, and so on. I enjoy the Bay Area, but in many ways, it's not very family-friendly.
Realistically, this leaves us with two options: a) we could consider the East Bay. However, as commutes across the various bridges are an hour or more each way, I'm disinclined to pursue that option. Or b) we could look into buying a place in the Necropolis of Colma. Housing prices there seem oddly depressed, which leads me to believe that they're having some sort of problem with the undead.
Zombies or no, it's the property values that I find terrifying.
 I have no good evidence for terrible apartment qualities in SF (though a Google search seems to support it). However, I'm inferring it because 1) the insane demand for apartments means that (slum/land)lords need only do the barest of maintenance, 2) paralyzing restrictions on any type of building or renovations ensure that most buildings are old and decaying, and 3) the relatively mild climate means that old drafty buildings are more tolerable than elsewhere.
 The go-to mantra for Bay Area natives is to blame Silicon Valley for all of their housing woes. However, Econ 101 suggests that the over-inflated housing prices are likely a symptom of demand exceeding supply. See The Gated City for a good overview of how homeowners have pushed for an incredibly restrictive building code that prevents construction of modern housing and ensures the ever-increasing value of their properties.