Barring bad weather in Denver, I'd connect DEN-SFO. It gives you a bit more time to connect to SFO-HKG flight. As you said, DEN offers more options in case you need to use them. Sitting in LAX past 10PM, you probably facing the last flight of the day to SFO by UA or Ted (of course, there might be flights to OAK and SJC to consider as last resort; however transit time between airports can be a big hurdle)