Ok, i'll list them in order of preference Net Org Info Biz Thats just my opinion others might not agree with me though
Biz is clearly the worst. The others have their applications. I do prefer dot Orgs rather than dot nets because they give a more serious feel to your website. I have also liked dot infos because of... the price .
I prefer registering and or buying domains in this order Net Org Info Biz I find buying info's real cheap but unless a real good domain..hard to sell for a good price and re-registering usually cost as much as a (dot) com! I avoid biz unless short character..I found expensive to register (more than a (dot) com at least the registrars that I use)!
The ones who posted the net, org, info, biz order got it right - that would be the order in which they are regarded in the domaining industry, although org has gotten hotter lately.
Never saw an ugly domain extension as dot biz. I have some though . I'm not sure if dot net is better than dot org as most people here assumes. In fact lately I'm thinking the opposite. Dot net seems a "secondary meaningless" extension these days (which I like) but dot org has an implicit serious meaning on it that may be more valuable for a developed domain than the, in my oppinion, meaningless dot net extension. Also I think dot org is easier to remember than dot net. Just my two cents.
I have about 25 domains with .com, .net, .org, .info, .biz, .cn, etc. My preference? None since with proper SEO, the website will perform well.
I would say .net is by far the best and most popular. But if you have a business then use .biz, and also .org is popular but not as known as .net and obviously a .com rules over any of them
.com is the best but if you can't get it - the rest should be alright. As I learnt - SEO is more important than anything in this cyber world.
dot org's & then dot net's are doing ok for us out of the list you posted. dot org's are getting good traffic from google fyi..