I personally find Wikipedia semi-useful as an ultra-high level view of topics I want to refresh myself on or get interest in. I wouldn't cite it in any remotely academic or meaningful forum, but it's an amazingly broad repository of information.

I hold this view mainly because a great friend of mine, a college associate professor, got sick of students explicitly violating his directive to avoid Wikipedia as a primary source and started randomly changing entries.

His first (and in my mind best) work was when another friend who is very into music mentioned a jazz musician that he really liked. The professor friend said, "Oh yeah, he's the one that composed the background track to I Wanna Sex You Up". Then he rushed off to update that artist's wikipedia page to reflect that statement. My musically-inclined friend called back the next day and said, "Wow, I never would have guessed that!"

Is this a good thing? Absolutely not. However, seeing the unquestioned acceptance of Wikipedia content has opened my eyes to the way that the system can be gamed or used to support lies or propaganda. Because a musician was wronged? No, its the principle. I now take everything I read on wikipedia with a colossal grain of salt. You should too.