Which domain name suffix after .net is worth the most? .org, .info, .biz or something else?

I would say .org because it is older and somewhat targeted towards organizations, although that use is diluted now.

But then I would say .us is next and perhaps even more than .org for sale to non-organizations. While it's not too common for the public to be aware of it, I think as time goes on and as people in the US find ad-infested pages when they type in domain names, they will start trying the .us names more and more. I think most .us domains are a better investment than the same name in a .mobi, but I'm still a beginner at this.

Definately .org Has lost some value over the years, but is still apart of the "BIG 3" so-to-speak.