This report covers only FNC Special Report with Brit Hume. Brit Hume is their least caustic conservative host. I wonder how the results would come in if you included Hannity and Colmes and The O'Reilly Factor. Granted these aren't "hard news" dedicated shows but then again, neither is Special Report. For example, 26.4% of the sentences on Special Report including a think-tank citation were observations. The other 73.6% were opinions. (Contrast with 64.6% observations for the liberal NYT and 64.5% for the liberal CBS).
This study also does not touch upon the punditry involved in giving one's opinion on the citations you're mentioning. Again, the incidence of opinion rather than observation on FNC and Drudge Report (44.1% observation) reflect that while they might be evenly citing liberal/conservative think tanks, their opinions thereof (the majority of their coverage, according to the report) are not at all considered in measuring the "bias" of the media.
Moreover, the number of sentences devoted to a reference (liberal or conservative think tank in nature) seems a very telling statistic. Even though their incidence rate for citations was about equal, FNC Special Report devoted 2.36 sentences to conservative citations for ever 1 liberal citation sentence. This was the highest rate. Second was the NYT (IMO, the most biased media outlet behind the FNC). This report does not at all take into account the nature of the commentary. You could mention a gazillion conservative sources, but if you color ALL them disfavorably or use them in non-partisan stories, the 2 liberal citations you used and praised are going to make you a very liberal news source.
More on why this is not a good indicator of media bias: It does not at all take into account the percentage of sources that "think tanks" represent in media coverage. If the percentage is low, this report holds little water. Second, if you reference a conservative think-tank for a story about children dying in jungle-gym accidents, why should this make your outlet more 'conservative'. I didn't see any language in this report talking about what percentage of the media outlets think tank citations were concerning stories on or directly affected by national politics.
Hannity and Colmes, O'Reilly Factor and other shows of the like are NOT news programs. They are commentary programs. The make their own opinions known on the specific news of the day.
Brit Hume reports the news much like Brokaw, Rather and Jennings. Unlike those 3, he brings it to you straight foward and without his own personal bias.
Drudge Gives you the stories as they are from the original source. He does not offer commentary on his site. If you want his opinion, you'll have to listen to him on sunday nights. His site does not offer it.
Therefore the report is accurate. Foxnews and Drudgereport present the most unbiased sources of news around. You are given all the facts and make your own decisions with little to no opinion at all.