For zip 92539, $334k insured value, wood-frame/1979, 1-story, $100k personal property, $15k loss of use, $20k building code upgrade coverage, 15% deductible, it ran $1002/yr. 10% deductible ran $1255/yr.

The question you have to ask yourself is this:
Is the cost of the destruction of your house worth the coverage?
With the $15k loss of use, you can move into a rental, etc. for the duration of reconstruction, while the $100k personal property should cover contents. You would be surprised how much contents actually cost if you have to replace them.
It is imperative, though, that you read the fine print of terms and conditions of coverage. If your dishes break, it isn't covered, so the child latches and quake (museum) wax from home depot is cheap insurance. There are also responsibilities that you have in the case of an event (like plastic sheeting the house to prevent rain damage after the event-reimbursable to a point).
There are other advantages to the coverage that many haven't thought about, such as water damage from broken pipes, etc.
If your house or your garage collapses onto your car, you may have a fight on your hands with the auto insurance company about the claim w/o EQ insurance (was the collapsing house comprehensive coverage or not covered? Again, read the fine print on those policies too!).
Good luck, and remember that insurance only covers you if you have it before you have any reason to make a claim