Rent everywhere in Silicon Valley is insane, and the VTA will take you between 1-2 hours to get anywhere (seriously; Mountain View to San Jose is an hour by public transit, but only 10 minutes by car if there's no traffic, or 30 in rush-hour traffic. Mountain View Caltrain to Googleplex is about 45 minutes by bus...it's about 5 minutes by car and 15ish by bike).
If I were moving and wanted to avoid cars, my first choice would be to live and work close to the Caltrain and take that. My second choice would be to live within biking distance, eating the elevated rent that tends to cause, and bike. If you go in to work around rush hour and have to cross 101 (via either Shoreline or Rengstorff), biking can frequently take 1/2 the time as driving, and even walking is comparable.