For my own blog, Joi Ito convinced me (quite easily, once he explained it) to use CC-BY-2.0. This is the attribution-only license, which allows derivative works, and which is not a copyleft license.
The key point that he made is that if newspapers want to reprint some editorial that I write in my blog, copyleft can cause them some fears and headaches. I was also considering a no-derivs license (after all, what I write in my personal blog is personal opinion, and do I really want people modifying my personal opinion and redistributing it?), but then he pointed out that translations are a derivative work, and of course I want people to translate what I write on my blog, since I'm always trying to speak from a global perspective to a global audience.
Some of this same reasoning applies to wikinews. But for wikinews, a really *big deal* is compatibility with Wikipedia. (Or, am I wrong about that? How often will a news story really need to have content from wikipedia that exceeds ordinary fair use or quotation rights?)
I don't know of any clever solution which gets us both advantages.
--Jimbo