Truly speaking the best Adsense alternatives are Clicksor and Chitika. Both cannot be used with HubPages. Adbrite, Bidvertiser, Tyroo are not so good enough.
I used many Adsense alternatives with my blogs like a research to find out which one would be the best Adsense alternative. I must say Clicksor is good. If your website/blog is receiving more traffic from USA and Canada then go with Chitika.