The Trappist in Oakland is a simple place, with only two cheese plates available as food. When I visited there was one server working the whole seating area so it was faster to walk to the bar and pick up pints yourself. They did a nice job with the glassware cooler water jet that lowers the temperature of your glass by a couple of degrees.
In North Beach, La Trappe is something between a restaurant, a lounge, and a bar. They have a full bistro menu (but could use more appetizers for those not in search of a meal) with some Belgian specialty foods, as well as a huge beer menu. I recommend getting there early to score a space on the plush seating in the lounge. Also, rumor has it mixologist Victoria Damato-Moran will be working there- which is odd because the place doesn't have a full liquor license.
In the Mission, Monk's Kettle is a small, bright space with upscale pub food and two dozen beers on tap. They have a combination of Belgian and other non-common beers, and the place seems always to be busy. Plan to get dinner if you want a table, or just pop in at lunchtime for a few pints (says the writer without a day job).