http://svng.com/tommasos/
I always consult the San Francisco/Bay Area Chowhounds. They are a lively and friendly bunch, always helpful and chockfull of recommendations.
According to the Chowhounds there, Tommasos is the "BEST" pizza in a city where good pizza is hard to find. I've been there twice and enjoyed the atmosphere, pizza, entrees, house wine pitchers, specials, and desserts, tremendously.
It is quite small, so go early.
It's reasonably priced and simple, basic Italian made with quality ingredients.
I really enjoy it and apparently some of CA's hottest and most famous dine there occasionally. It's not trendy, though.
It's two blocks from the famous and interesting CITY LIGHTS bookstore.
Reading is a right. Censorship is not.