Couple of years back Santa Monica would be a definite choice. Then, with skyrocketing rent prices, all the cool kids, followed Google's example and moved to Venice beach. Now the same problem is happening to Venice Beach. The prices become too high and the space is not nearly enough to satisfy everybody. Among new cool startup-y neighborhoods are Culver City, Marina del Rey and Playa Vista.
So considering the distances are really quite big, you probably should aim for one of those, especially considering they are quite close to each other.