PolitiFact.com is a nonpartisan fact checking organization which won a Pullitzer Prize in 2009 for its work in fact checking claims and publishing reports about the claims of various politicans during the 2008 election. They publish not only their findings, but summaries of the research and facts which led them to their conclusions (and yes, I read PolitiFact regularly, and they fact check and criticize Democratic claims as well as conservative ones). Their vote for the biggest lie (or set of lies) perpetrated on the American public in 2010? Republican arguments portraying the Democratic health care reform bill as a "government takeover" of health care.
I thought it was an interesting read.