I was in San Diego for one night for an appointment the next morning, and decided to try out the Gaslamp Hostel. It was great! Really nice decor in the common spaces, clean, lots of light, and fairly comfortable beds. They had lockers in the room, with electrical outlets inside; they also have locks for sale for $5 if you need one. The kitchen is well-equipped, and there's a dining area that's open at all hours. The shared bathrooms and showers were clean.
A hostel isn't for everyone, but as long as you're aware of what it is you're getting, this is a great place! Thanks for a nice stay!