Well, making people register to edit/create articles is a good idea, I think. Perhaps in the future they could add some features for users to authenticate themselves. I really don't feel in articles you want to be held to a higher standard that you should need anonimity. On the other hand, there may be a lot of good contributions that would not occur without this.
I do know this much, reports against the credibility of wikipedia are generally overplayed. I find a great deal of good information there all the time. I'm really surprised at how thorough articles are on most subjects. It is definetly a good and useful resource.
I would advise people never to accept a single source for anything, especially subjects which are common to have bias in. So if it deals with politics or controversial issues, then taking wikipedia with a grain of salt is a good idea. I still think it's useful in many cases there, but realize that what is said may not be fully accurate, and if anything sounds particularly inflammatory or makes some serious charge, you should check it out more thorougly before repeating it.
Perhaps wikipedia could seperate out articles that are more solid over time into a seperate site. These would not be directly editable but would be a bit more solid. I believe that the previous project the founder was doing (Nupedia?) was to be more like this. Anyway, I think the core of wikipedia is good, and I definetly wouldn't want to see contributions to it go down, but a way to seperate possibly biased or incorrect articles from those that have had more vetting would be good.