Like any tld, they are worth whatever someone is willing to pay for them, but that doesn't mean a generic one word domain name is worth money and your GODADDY example is simply idiotic (the new GTLDs are heavily geared towards looking after trademark owners) and should be avoided like the plague (ie you will most likely loose it and be out of pocket for your troubles)
The problem with the new GTLDs is simple, the public isn't aware of them and there are too many available.
What will be worth money?
If it was that easy, then everyone would be doing it.
Simple nutshell advice, a $50,000 sale is not guaranteed and at the moment you are more likely to encounter $80 offers (ie base registration x 2)...is that worth your registering a domain and renewing it for several years till the public catches up, assuming the extension you elect to register survives (.XYZ is being inflated by freebie registrations, .CLUB has a good chance of survival but finding a decent name is in turn getting harder while .GRIPE may well .FAIL to survive because it has single letters available for around $50 that just are not selling and that has to be a bad sign)