I have to admit, I've seen some pretty decent names that have almost all tld's taken except the .ws and maybe .cn or .tv...Are they that useless? Could they be worth anything at all??..If you have 2 common words together and all other tld's are taken but the .ws and .tv..is the .ws worth it?
Depends what for do you want to use it. I got pretty decent ranking .ws name, all other tld's were gone years ago. However for pure domain speculation or resale, many people are hesitant to purchase anything except .com. anyway once you get the site going, I bet all such prejucide goes away and all is only down to how much the site is earning...
for seo, using any common generic domain tld doesn't matter. so, .ws is fine if you seek search engine traffic only.