Why didn't Dooku say something (spoilers)
 

He obviously knew who Palpatine is since:

1) He acted shocked when Palpatine said "kill him"

and

2) In AOTC he said the republic senate is controlled by a Sith lord.

When Palpatine said "KILL HIM" why didn't he yell to Anakin "HE IS THE SITH LORD" for some revenge?

what good would it have done?
die like a man, or die screaming like a bitch
either way he was going to die

If he wasn't in too much shock to speak, I think it would have been something like: "Holy FUCK -- he cut off my hands! Just like I cut off his arm! My uppance has come! Fucking hell -- this HURTS!"

should have, could have, would have.. blah blah blah.

In one of the drafts he does say something. Anakin then responds to being confused about what dooku said

Yeah...I thought he said something in the novel.

Dooku's too much of a Bad Mutherf'er to start whining like a little bitch. Besides, Lee's look said everything that needed to be said. That one shot Lee was able to convey a "what the f?? I'm your right hand man!! Why you telling this chump to kill me?". That's acting man.

Agreed. Too many times in the Star Wars movies, Lucas shoves in a bit of lousy dialogue instead of letting the actors convey ideas and emotions non-verbally. This was a good use of staying quiet.

if he says at that point..."He's the bad guy too!" Who would believe him?

Besides, who's to say that Palpatine couldn't have been holding Dooku's tongue.

The look said a thousand words....or maybe just 3 - WTF?!

The audience!

:)

slightly off topic, but is Dooku ever referred to as Darth Tyrannus in the movies?

Rarely. One of a few dozen nits that I have to pick with the prequels.

Jango mentions that he was hired by someone named "Tyrannus". And, at the end of Episode II, Sidious refers to Dooku as "Lord Tyrannus". Other than that, there are zero references. Anyone who hasn't done some outside research -- web sites, books, etc. -- will likely not even realize that he has a "Darth" name.

Oddly, there isn't a single Tyrannus reference in all of Episode III. He's mentioned many times, and it's always Dooku.

Wow...I'm surprised nobody has said the movie was ruined cause lucas didnt have Dooku say something...

The thread is still young though.... "I need more Cowbell"!!!!!!!!!

the scene felt like his Saruman role from Return of the King (Extended Edition) - a "let's kill his character quickly to get him out of the storyline"

One thing that has always puzzled me is replacing Maul with Dooku. Dooku just didn't seem that intimidating to me and I would much rather have seen an Anakin/Maul duel than Dooku. I know Dooku was needed to "lead the separatists" and Maul's near mute status wouldn't have helped that, but it seems like that could have been handled with Maul the same way Anakin was sent to do Palpy's bidding with the sepratists.

Well I'd guess the list of Jedi that Sidious could have turned wasn't that big. Consider Qui-Gon's death, seducing Dooku makes sense story-wise. Also, Maul probably wasn't worth much more to Sidious anyway. Judging by TPM, Sidious has to tell him what to do while Dooku in AOTC was much more self-sufficient. He was needed for ordering the clones, erasing the archives, negotiating in person with the seperatists, and finally starting the war.

Each Sith Lord, even Vader, is a pawn to move his plans forward.

I've tried to explain my views on the sith and how they range.

Maul was brute force. Pure evil. Dooku was presence and nobility with a slight bit of "good and bad all depends on how you look at it". General was half man(alien)/ half machine. All these are aspects of Vader. So while each one on their own wasn't all that was needed, combined they make the ultimate sith bad ass.. Vader.

Grievous was Sith?