I don't. If you can get a good keyword and plan to obtain traffic through search engine marketing and links then it's cool. But people just don't take that extension seriously enough (if they even know about it at all) to depend on it for word of mouth or branding.
Personally, I wouldn't touch any country code TLDs that aren't relevant to my target market. So if I'm not doing business in Samoa, I wouldn't use a Samoan domain name.
I would never go to a site with .ws unless a friend recommended it through word of mouth. Even .net causes some "iffy" issues with some people. Ironically, most people choose .net, before .org, but .org has almost as much value in my opinion than .com.
I would consider www.a.ws - but 1 letter domains are $50,000 for 2 years, 2 characters is $1000 etc..