The Marriott is the best, a couple of blocks to the Con, but pricey . Another alternative are: The Orchard Garden, Galleria Park, or Holiday Inn Chinatown which is OK, if you are budget conscious. Its about a 10 minute bus ride (you'll take the #15 or #30 Muni bus line) or 20-30 minutes (5-8 blocks) walking distance to the Con from those three hotels mentioned.