With 700,000+ square feet of space, the Moscone Center is (by far!) the largest exhibition space in SF. Most events on the convention calendar are professional and/or academic - both specific and expensive - there are notable exceptions like WonderCon and the SF International Auto Show.
The "building" is actually three massive structures, the original Moscone Center South sits under and around Zeum among others, while Moscone Center North (1991) neighbors the Metreon and expands below Yerba Buena Gardens. The newest Moscone Center West (2003) is predominantly above ground and boasts more modern luxuries, like windows :)
For less professional/academic events, check out the Concourse Exhibition Center.
Address: 747 Howard St, SF
Website: http://www.moscone.com
