It's not as much a hierarchy as different areas appealing to different types of people and families, with a big property size/walkability dividing line being I-280.

Let's say you have the nice problem of spending $10M+ on a house. If you want acreage and multiple guest houses and privacy and your own vineyard and stable, you might end up west of the 280 in Woodside off of Whiskey Hill Road. This is the Larry Ellison, Steve Jobs (Jackling House), Thomas Siebel, and Gordon Moore approach. Trivia: I was talking to a general contractor last week who said Gordon Moore's home upgrades/maintenance on his estate in a private valley on the north end of Woodside kept his business afloat during the 2008 downturn. If you want significant acreage, you'll need to budget tens of millions.

But in Woodside you don't get very much within walking or horseback distance, except Roberts Market/Bucks/Woodside Cafe. If you prefer the south bay with even less within walking distance, you might end up in Los Altos Hills or the hills overlooking Saratoga or Los Gatos. Portola Valley is another option.

If you want a 10,000+ ft^2 estate behind walls close to El Camino, you choose Atherton. If you want to be able to commute to SF and don't mind cooler weather, you choose Hillsborough. If you want to walk to a thriving downtown area with excellent restaurants, you (likely) lose the walls and gates and buy a more modest house for the same price in Palo Alto. The Palo Alto approach is what some Google and eBay executives have done, what Steve Jobs did in addition to the Jackling House, and what Tim Cook reportedly has done.