A commuter bus is nice, but being in CA, you'll be in not only prime motorcycling weather, but also in the only place where you can split lanes legally. I would definitely be looking to take advantage of that if I were moving to the area. If you do plan on commuting on your own at all, 280 is a much better experience than 101.
I lived there years ago, in Palo Alto and Mountain View. Spent a good amount of time in the neighboring towns as well (Menlo Park, Atherton, Redwood City, Sunnyvale, Los Altos, etc.). They're all good areas, though I recall Mountain View and Sunnyvale to be kind of a symptom of the dot com boom--lots of apartment buildings and convenient shopping and such, but not necessarily a whole lot of personality. Granted, this was 10+ years ago, so some things may have changed.
I hadn't heard of the term "tri-valley" before, but my impression of most of the east bay was that it was more affordable, for a reason.