ABC’s Nightline–once considered past its prime and on the verge of cancellation–has thundered to a ratings win for the fourth quarter 2010, beating both David Letterman‘s Late Show and Jay Leno‘s Tonight Show among total viewers.

In the just-completed fourth quarter ratings compiled by Nielsen, Nightline ranked No. 1 among total viewers (3.93 million) and adults 25-54 (1.61 million).

Is Jay Leno not satisfied with how despised he is right now? The former — and soon-to-be — Tonight Show host been taking hits from arch-rival David Letterman, sure — but did he have to go after Letterman’s wife? It doesn’t take a genius to know that Leno’s attack is a low, mean blow, but check inside to see exactly what he said.

Jeff Zucker was on Charlie Rose last night, somewhere between Jay Leno and Conan O’Brien on the clock — though clearly not between them in allegiance. Lest anyone think that an 11th hour reprieve for Conan is possible — dressing in orange for rallies can only do so much — It seems clear that Zucker has moved on.

Again, just to be clear: Jay Leno would like you to know that this is not his fault. Here’s what Leno would like you to know: He doesn’t have an agent or a manager — a handshake is all right by him. His version of the Tonight Show was #1 when NBC asked him to [...]

The setup: Fred Armisen as Larry King talking it through with Darrell Hammond as Leno, Bill Hader as Conan, Jason Sudeikis as a manic David Letterman, and, briefly, Will Forte as Carson Daly. (No Jimmy Fallon though, which might have been an easy get!) Hader and Hammond, usually wickedly sharp at impressions, were weak here, as was the thin material.

Conan O’Brien’s kiss-off letter to NBC is going to make him a hero, not only to people who started off loving him, but because he’s been cast as the underdog here, unfairly subject to the failings of Jay Leno and fickleness of NBC. But Leno wants a bit of that victim spotlight, too.

The news yesterday was that Conan O’Brien was not happy about NBC’s shenanigans. On his own show, he joked about it, zinging NBC with a much lighter touch than Leno, but still. “Welcome to the show everybody,” he greeted the crowd, which seemed to cheer for him extra-long at the start. “We’ve got a great show tonight – I have no idea what time it will air, but it’s gonna be a great show.” Video inside!

TMZ reported earlier today that, according to unnamed sources; “Jay Leno is going back to his 11:30 PM time slot, and it’s looking like Conan O’Brien is the odd man out.” While nothing has been officially announced, Bill Carter reports that NBC executives “did not deny a report posted by the website TMZ that NBC was considering making the switch and replacing Mr. O’Brien at “Tonight” with Mr. Leno.” Update – Carter now reports a possible line-up being bandied about at NBC…