Biking is my main mode of transportation. Bike to work, for groceries, and to get around in general. Good weather and a decent bike with saddle bags helped the cause.
But life in the bike lanes around Santa Clara isn't much fun. First of all, there aren't many bike lanes and connectivity is generally poor. Google maps shows a 24 step route for a 5 mile commute. Most of the times, bike lanes are basically wider parking lanes. You fervently hope that a door doesn't swing open as you speed past parked cars. There are a few bike lanes on expressways too. 
Definitely not for the fainthearted, including me. And then there is the issue of parking. You will have a million square feet of parking space in parking lots, but not a single bike rack to lock your bike to. And when they do have bike racks, they don't seem to know what to do with them. See the picture below. Its a pity that the bike infrastructure is abysmal in a place that is conducive to year round biking. But you have to make do with what you have got. 
There is only so far you can go on a bike. And that depends on the time of the day, weather, fitness level, bike route connectivity etc. Besides biking there is the option of public transport. The Caltrain is useful, but only if your origin and destination is close to a station. I live pretty close to a Caltrain station, but alas, the destination often isn't. The good thing is that you can put your bike on the train to help you get around when you get off. The bus service is quite miserable. I can definitely get to a place much quicker on my bike than by bus. Take for instance my daily commute. I have to leave home at 7am to reach office at 8am if I take the bus. And I live only 4 miles from work, which is 20 minutes biking!So biking is the main mode of transportation. Anything within 5 miles is fair game. Above that, it depends on the errand at hand. So no weekend getaways, meeting up with friends or exploring new places. I used the Zipcar a few times as they have a few stationed about a mile from where I live. But in the long run, with frequent use, the costs can add up quickly. My room mate lent his car to me a couple of times when he wasn't using it. I used car pooling the few times when I have gone hiking. I requested/begged people to drop stuff home when I bought things of craigslist. Some people are really nice!
I have finally caved in and decided to get a car. A car in the Silicon Valley is a necessity or a luxury, depending on the way you see it.
