This is actually a hard one. The top spot belongs to either Maul or Ventress, without a doubt, but one could easily make a case for either for them. However, I'm tempted to go with Asajj.
Sora Bulq was pretty good, and I doubt that the relatively raw Anakin or a somewhat washed-out Qui-Gon would be able to take him in combat. However, he's not far ahead of either.
The bottom spot is also a tough one to decide. Qui-Gon's still good, and his experience and clarity of mind could put him slightly above Anakin as a combatant. However, even though he's relatively new to whole Jedi thing, and is decidedly brash and reckless, Anakin is young, strong, very skilled, and aggressive as hell, all of which could help him here. These were also traits shared by the admittedly superior Maul - just thought I'd throw that in there.
Why is AOTC Anakin so low?
He's above AOTC Obi-Wan according to the movie. Even after taking a full-on blast of Force lightning he gives Dooku a much better fight than Obi-Wan and Dooku is even somewhat tired afterwards.
Obi-Wan was dispatched with so much ease it was painful.
__________________ Earth is a beautiful addition to the Galaxy...but an even finer accessory on the hand of a God.
According to the Attack of the Clones novelization, the second time that Anakin Skywalker engaged Count Dooku on Geonosis, he found that the boy was most decisively a worthy adversary. Not near enough to best the Count in combat, of course, but a threat nonetheless. This is further supplemented by Dooku's own thoughts in Labyrinth of Evil, where he muses that -- when angered -- the boy had proven himself to be a "powerful opponent". To be a threat to a duelist as accomplished and as powerful as Count Dooku, one must be a skilled combatant indeed.
That said, it is arguable if he could best Darth Maul, who was able to defeat Anoon Bondara in single combat, a Jedi whose technique and ability with a lightsaber was "second to none" in the entire Jedi Order, as well as his ability to overwhelm Qui-Gon Jinn, a prolific duelist in his own right. Likewise, one of the foremost of Anakin's advantages over most combatants is his ferocity and physical prowess. Though he's not an outrageously muscular man, his Force connection and general method for combat make him nigh overwhelming as later shown in Revenge of the Sith -- the longer a fight progresses, whereas most people will tire, Anakin only serves to get stronger. He might not find that advantage so clear cut in an opponent like Darth Maul, who is by far, the more lethal duelist when it comes to physical ability and martial prowess.