Single Letter Domains like .ac etc any value?

[krossat]

I am getting a chance to purchase a single letter domain name like th efollowing:
a.tc

Just wanted to know whether there is any value of a single letter domain with obscure extensions like .vg, .tc etc?
Should i go ahead with the purchase, or its a bad idea to get a single letter domain with these other extensions which dont have a major value as of now...?

Thanks for the help.