Let the cage fight begin ... Your personal opinion about biased probably says more about you than it does about the news source.
Now, I read practically every single outlet on the graph (I derive my input from google news which aside from this forum and the local weather is my other homepage) except the lower left and right corners which I only bother with extremely rarely. I didn't even recognize a few of the names

If I had to make this graphics from scratch, I'd place everything similarly. I'd move Slate and the Guardian half a field to the left. I also note that AP and Reuters aren't well-placed but that's mainly because they aren't in the business of doing analysis but rather in being "fast and neutral" and charge a pretty buck for speed. In that sense, they're fairly placed except it's kinda misapplied/misleading to put them in with the rest. I'd put Bloomberg around where FT is.