Very true. The answer would be relatively easy if the question is about current domain market prices. If it's about what domain extensions are best for the future, especially in pure domaining terms, we are potentially looking at a very long thread...
Like it's been said, from SEO perspective, it doesn't make that much of a difference. However, in terms of resale value, there's a huge difference.
I personaly are not too keen on dot net since I have already had to rebrand and name an ex dot net to a dot com. Small easy to name generic words are fine for .net, org is still quite useful in some cases. .info has a lot of uses and will continue to grow. .us also should do well as US businesses/companies look to alternatives to dot coms
What type of site are you planning to build ? Long term, need to establish yourself, catering to the global market- preferably com Make a site and sell to buyers who don't care about the extension- info. Non profit organisation- .org