I use Josh Marshall's writing at TPM as a baseline for shrillness; Josh, maybe because he's committed to building a media empire--and thank the God(ess)(e)(s) of your choice for that; look at the other media empires we're dealing with--doesn't live the Shrill in the way that your average C-list blogger does.
And maybe it's just me, but Josh seems to have gotten much more shrill, lately. When he does, I tend to take that as an indicator that there even more than usual to be shrill about, since Josh isn't driven by his Inner Shrill, but by "events, dear boy. Events."
So, fasten your seatbelts.
UPDATE The same goes for Kevin Drum. Here he is on Rudy (excellent post, read the whole thing):
Choosing the best presidential candidate among the 2008 contenders is a tough job. Picking the worst is easy. Rudy Giuliani is the guy you'd get if you put George Bush and Dick Cheney into a wine press and squeezed out their pure combined essence: unbounded arrogance and self-righteousness, a chip on his shoulder the size of a redwood, a studied contempt for anybody's opinion but his own, a vindictive streak a mile wide, and a devotion to secrecy and executive power unmatched in presidential history. He is a disaster waiting to happen.
Yep. A good operational definition of shrill would be "To the left of the Overton Window." (By implicit contrast, a winger is never shrill; no right wing position can ever be too crazed to be beyond the bounds of acceptable discourse, as practiced in the Village.) Of course, the function of our famously free press is to keep the Overton Window firmly fixed in its current position. Which would be fine, or at least not lethally dangerous to the Republic, if reality were static relative to the window. In fact, the country--in almost the words of John Mitchell--is being shifted so far to the right you won't recognize it, so the Overton Window is rapidly becoming even more disconnected from reality. The degree of shrillness is a function of that disconnect, because the bounds of acceptable discourse can't describe reality any more.