Now the real brain teaser is how the heck Ventress managed to Force Choke him?! Even if she was in some temporary rage boost, surely that couldn't have made her more powerful in the force than Count Dooku!
I don't think Ventress was much less powerful, than Dooku. It's just Dooku could utilize his powers much more effectively.
And actually, anger can give very huge power boost. If we think about it, anger cannot be amplified willingly, it's an emotion that gets stronger depending on circumstances.
Before Ventress fought them, Dooku said that she failed and that she is no longer his apprentice and shall die. At the same time her hatred for Jedi increased even more as they were the reason of her failure, that they kept spoiling her plans and then Obi-Wan didn't help the matter by giving taunts.
It's not a typical encounter, she experienced far greater anger, than usually.
Same with Opress. Both Ventress and Dooku treated him like a smear, chiding him and telling what to do. He got enraged and as the result unleashed it on them, then on Obi-Wan and Anakin and finally giving that Force blast knocking everyone over.
I read book The Old Republic: Deceived and it shows very well how anger can greatly amplify power.
On Alderaan on negotiation about piece treaty between Republic and empire Aryn Leneer - a Jedi Knight felt death of her master. Two Sith sitting and smirking at front of her became target of her rage. She gave immense Force blast, Sith blocked it but still were pushed against the wall, however, two statues on sides got shattered into pieces. Then one of the Sith took out lightsaber but she simply yanked it of with the Force. She didn't even want to take out lightsaber, she wanted to quash them with Force alone but fight was interrupted.
In another scene Malgus came to medical center on blockaded Corruscant by Empire. As he walked outside he felt how people despised and feared him. His anger started increasing and he was absorbing their fear and suffering. He clapped his hands and gave Oppress like Force blast that turned cars upside down, injured/killed people and broke windows. And he wasn't described to make a particularly big effort in performing this feat.
In first fight with Malgus Aryn gave in to her rage completely(he killed her master). Whole fight she was on offensive, successfully blocked his lightning and seriously injured him with lightsaber. But fight was interrupted and she decided to fly away as killing him in anger would lead to darkside.
In their second fight she tried to fight without anger, she wasn't as offensive anymore and failed to block Force lightning with lightsabers like last time and as the result lost fight.
Malgus after fight was angered about a lot of things. Then he killed Twilek girl he truly loved, which can be referenced to a Sith saying: "He will sacrifice his love". It caused him enormous pain and far greater anger. After he totally dominated a Sith Lord he rivaled and the implication of that fight was that Malgus's anger was far stronger.
It's a great book. Strongly advice to read it.
Apart from these situations there are far more examples showing what enraged Force user can do. For instance Galen Marek's feats were achieved not just because of his potential but because he was psycho.