This came as a bit of a surprise. Peter Jennings was the last of the Big 3 Triumverate -- Tom Brokaw and Dan Rather being the other two -- to depart the national scene. (It was only four months ago that he announced he had lung cancer. One would have thought he would have survived longer, but that type of cancer is tricky to contain. The tobacco lobby must be having a conniption fit now -- but that's another topic.)
Of the three, Jennings was the most cosmopolitan. It was this air that enabled him to earn a more trusted reputation than Dan Rather.
A part of it came from his Canadian citizenship (despite his tenure, he only became a U.S. citizen in 2003, having begun the process after 9/11), and the fact that he started as a foreign correspondent for ABC News. This gave him a detachment from American domestic politics that enabled him to avoid the charges of partisan bias that always plagued Dan Rather, and to a lesser degree Tom Brokaw.
(Note that I say partisan bias, not liberal bias. Jennings learned his craft from the CBC, after all.)
This type of detachment is rare in American journalism these days; the plague of advocacy journalism has largely erased the news judgement model that Jennings had mastered. The model will come back eventually, but it will be a while before someone emerges who can practice it as well as Jennings could.
Jennings' legacy is as an example of how good news presentation should look -- not preachy, not proud of the methods, but just the facts that Americans needed to know. Confidence and class -- that's what good news anchors should strive for. He'll be missed.