There is another big reason why Snowden may have chosen HK. A few months ago the HK high court ruled that the process for applying for asylum needs overhaul, and until that happens all extradition proceedings for asylum seekers are on hold. So Snowden simply needs to apply for asylum in HK to significantly delay things:

http://www.globalpost.com/dispatch/news/regions/asia-pacific...

I haven't seen much coverage of this in the US press, aside from Slate & CSM. The rest of the media seems more interested in Snowden's girlfriend and scholastic record instead (sigh).