There are so many people in south & west NA, and wow at some of these arguments. When it comes down to the hosting of servers you have best results to put them on the main hubs (that most traffic ends up going through anyways), which happen to be Chicago, dallas, San jose, and bleh i'd have to look at a map of all the big pipes to remember the less important ones. Sure, you can host one in Seattle, LA, Salt lake city Utah, or some other place as they get OK hosting, but you'll get best results off of the main spots.
Also, Chicago has some of the best latency for east coast (and everywhere close to it). You can't argue that one, it is true. Pretty much anywhere on the east coast, sin florida due to being far away, is going to have 70 or less ping to Chicago. However, anyone west coast is going to have a ping of at the least 80 but usually higher to Chicago.
I say all this but nobody cares. Just do some tracerouting and see the hubs they go through, you'll see.
tl;dr If it is for specifically west coast you want it hosted in San Jose. Most west coast traffic passes through San Jose anyways. It gives the best latency to anyone in the southwest excluding the option of it being hosted in the specific town you live in, which is greedy, etc.