Well, it depends on what you want. If you're here on a day Alesmith is open, Ballast Point is also right up the street. If you're staying in that area, I'd go to O'Briens. If you're closer to downtown, I'd go to Hamilton's Tavern and Blind Lady Alehouse. As far as other breweries... Stone is the big one. Alesmith is tiny and cool, but there's not much to see. It all depends on what you want to get out of your trip.