I have great respect for Keith Olbermann. His rhetorical style is sometimes over the top, but he speaks articulately and with passion (the former being all too much of a lost cause on cable news recently). He consciously fashions himself after Murrow, and he makes it work.
If you're interested, these are some more of his better segments:
On Bill O'Reilly:
http://youtube.com/watch?v=QHUGCkROwJE
On Dissent and Torture:
http://www.youtube.com/watch?v=C3WUdk2NVws&NR
On Rumsfeld:
http://youtube.com/watch?v=B5eOvaWKY3g
On Dissent, again:
http://www.youtube.com/watch?v=ogDkd87_57A
On Ground Zero:
http://youtube.com/watch?v=mH7zaxAGMWk
And his appearance on Colbert, which is entirely different in tone, and is pretty hilarious:
http://youtube.com/watch?v=wwrOqpXmp44