Californians, Which City Should I Visit?

I'm a fairly broke college student who really, really needs a vacation. My friend and I would like to visit California for about a week. We are from the East Coast and looking for a change of scenery. That being said, what city should I visit? Here's some criteria/info:

• We would be 21 at the time of the trip
• Walkability is big. We like to avoid spending money on Uber/Lyft.
• We like to eat everything and anything
• We love the beach
• We enjoy a good club/party scene for nightlife
• We really enjoy museums and cool shops