I think Wikipedia is a good and fairly reliable source of information on just about anything you can think of. Sure, people claim about inaccuracies, abuse and what-not, but that's just inevitable and it gets corrected in a couple of days. Wikipedia brings up the facts fast, which is the best thing followed by a google search. I've found Wikipedia invaluable in getting info on something I've never heard of before.
Wikipedia also serves as an episode guide, a geek guide, a music guide, a research tool and tons of stuff. I'm a proud Wikipedian under the ID "Sabretooth" (look me up!).