I can't understand why DC and Colma remain so cheap (comparably). Sure, the area doesn't have as much walking distance locales but a quick Bart ride will get you anywhere you want to go. Are people really that sensitive to small inconvenience?
[0] In Palo Alto home prices are artificially high in part because the schools are great and it's very hard to build new houses there. In Mountain View and Sunnyvale there is a lot of newer development and the schools are a little worse. This trumps distance.
I've looked at apartments there a couple times, and while it's vastly more affordable than SF, the climate + distance outweighs the upsides (for me anyway).
I've actually thought about moving out of SF proper into Colma someday because it seems underpriced for its location and amenities. Daly City is quite nice too -- agreed that that part of the map looks like the best deals around.