Silicon Valley has been a hub of all things web. In one way or another every web business has a connection there. The hub has many spokes.
Because there are so many spokes, you don’t need to look for web design firms from the valley, you can find great designers and developers that started in the Bay Area but left for some of the less intense more affordable areas such as Sacramento and its bedroom communities. Heck, my firm is in Chico where the living does not get much better. When you work with a web design firm that not only loves what they do for a living, but enjoys where they live, you are going to find a more enjoyable web development team. It kind of like the great cheese comes from happy cows. There are a lot of happy cows around Sacramento.
Don’t pigeon hole yourself to working with someone local unless you live where happy web teams live. You will not only have a more enjoyable experience having your web site built, you will likely save a few dollars. The best web designers stay busy no matter where they live and that why the best web designs come from Sacramento’s neighbor to the north, Chico.