I believe informative hubs that answer questions people have are the most effective. People tend to look up things on the search engines (where most traffic comes from) when they want to learn something.
If you write the hub and keyword research it properly for "how to fix a widget" and someone Googles how to fix a widget, chances are your hub will be high enough in the search engine results that you'll get a good deal of traffic.
I also find that people are more likely to purchase things related to your hubs (amazon or ebay products) if they feel you have taught them something valuable.
The page view money is nice, but the clicks on ads/products are what you are after to make the most money. I would say keyword research and use that to answer questions/provide solutions people are searching for.