Personally, I get my second highest amount of views from Reddit, with Bing being a close third. I would estimate that Google makes up roughly 70% of my traffic, with HP, Bing, Reddit, and assorted other sites making up the rest.
As you said, my first is Google (organic), then comes hubpages.com, 3rd is direct search, 4th is Google again (referral) and fifth is Yahoo. Ask and Bing and other sites come only after these. I guess Facebook would be a nice traffic source for me too, but so far I did not posted my hubs there.
You can help the HubPages community highlight top quality content by ranking this answer up or down.