Count Dooku was a man of many diciplines. He trained with Jedi, Sith, Wizards and Vampires. In fact he added the title of Count to his name after hanging out with his good friend and fellow vampire down on Sesame Street.
The Jedi Years
Count Dooku was trained by Yoda in the ways of the force. In general he was considered one of the more bad ass Jedi only Yoda and Mace "Do I look Like a Bitch" Windu were considered his equals. He also trained Qui-Gon Jinn who ultimately let him down. Eventually Dooku left the order when Applebees stopped their Jedi eat free policy and the Order refused to investigate whether or not management was now being influenced by the Sith.(It had in fact been purchased by Palatine Enterprises LTD)
The Wonder Years
After leaving the Order Dooku went in pursuit of new disciplines to devote his life to. First he joined the Vampires but after the inherent weaknesses, like the aversion to light, and the fact that Dooku wasn't really a night owl he went looking elsewhere even though was considered one of the most bad ass Vampires around. Eventually he ended up with the Wizards Guild and quickly rose through the ranks to become their leader. As the White Wizard he got his first true taste of being a bad boy when he teamed up with Sauron. When he saw how the ladies loved it he knew he had found a calling. Unfortunately a couple of midgets were able to defeat Sauron, and Dooku was once again in search of something new.
The Sith Years
Dooku was eventually picked by Darth Sidious (or ol Sid as Dooku was fond of calling him) in free agency and began to learn the ways of the Sith. Sidious set him up with an army and even let him run a war, which the chick totally dug. Dooku was rolling in the honeys after teaming with ol Sid. Of course being bad has its consequences and Dooku ended up having to beat up Obi-wan and Anakin, which was really more fun than he thought. However after fighting Yoda he realized there was still more to learn from ol Sid.
He later turned one of his favorite honeys into his secret apprentice but she disappointed hm liked Qui-Gon did. Finally he got to fight Obi-wan and Anakin again. He thought it would be a cake walk but Anakin laid the smack down like he never expected. Fortunately his master ol Sid was there but then Sid totally PWN'D him and told Anakin to kill him. Which he did.