It was obvious that Obi-wan and Anakin didn't have a chance against Dooku, while Yoda morte than held his own. Mace Windu's (suppossed) unusual lightsaber fighting style would've allowed him to hold his own against Dooku. Darth Maul's speed, ferocity and double-bladed lightsaber would have been interesting against Dooku's calculating precision. Qui-Gon's knowledge of Dooku's fighting style from his teachings (Dooku was Qui-Gon's teacher . . . or so Dooku claimed) would've certainly given him an edge in using counter-techniques. However, Darth Vader vs Darth Tyranus would be most interesting. Dooku would have the edge with skill. However, Vader with his awesome power from his anger (as we saw in AOTC) would more than compensate with sheer aggression and ferocity.
Vader, as GL has stated, is too crippled to fight well. Dooku would beat him easily.well I guess Vaders strength in the force might have aided him, and that he was full of dirty tricks too.
It doesn't matter about Vader's power with the Force. It is fairly clear that regardless of Force power, sabre skill counts a whole lot more (Dooku is MUCH better than Obi-Wan with the Force but needed a sabre to beat him).
And regardless of anger, power, or otherwise, GL made it clear that the OT combatants are not as good as th PT ones, and that incluides crippled Vader.