Humm...there's a question! How about "stability or insecurity?" Maybe "A future for your family, or everybody's on their own?" Perhaps "Owning something Real, or owning nothing Real?"
Buying a house is not just a shallow question of interest rates or appreciation or down payment or shadow inventories.
Owning Real property has traditionally, for centuries, been your family's legacy.
Somehow, over the years, we all got swayed into thinking that Real Estate is just another investment. 
It's so much more than that!
It's your identity, it's your power, it's your independence.
When you own your own house, you are in control.
You can add-on, you can remove walls, you can paint, your can customize.
Or, would you rather be subject to some landlord's approval, and then later on, be evicted?
Yes, you CAN get evicted, even in SAN FRANCISCO ;-( 
As for the investment aspect, yes, values have dropped over the past few years.
12% down on average in San Francisco give or take, depending on which area.
But, that's not like 50% in the central valley, or 80% in Detroit!
WHY? because this is GREAT place to live. Everybody likes it here and there will always be strong demand!
Therefore, the market WILL bounce back. It may take several years. But, you gotta live somewhere, right?
9 times out of 10, your mortgage payement can be less than rent payments! 
So, I say, don't hesitate!
The sooner you get in the game, the more your will accumulate...not just equity, but LEGACY!