This is a very interesting topic, and there are many cool ideas already posted.
Here's mine:
The jedi stand back and have a spot of tea, chatting about the nature of the Force, galactic politics and whatnot, meanwhile;
The Sith quickly grow bored with the no-fun jedi, and decide to find out who is strongest. This topic alone is highly debateable, and since it doesn't really matter in the end, we'll say Vader wins (personlly, I would favor Dooku in a Free-For-All).
After destroying all his rivals, Vader attacks the jedi, who (in defense!) easily dispatch him.
Another point of view:
Since Anakin and Vader can't really exist at the same time, let's replace Anakin with, say, Bastila Shan. Here's my match-ups:
Revan vs. Skywalker
Malak vs. Yoda
Sidious vs. Windu
Vader vs. Kenobi
Tyrannus vs. Jinn
Maul vs. Shan
In order of straight-up Force power, not counting intangibles like wisdom, or coolness. All times are approximated.
Revan defeats Skywalker easily. Revan (the way I played her) understands the Force more completely, and has better lightsaber technique. It would be a grand battle to watch, but Luke really has no chance. 30 minutes
Yoda defeats Malak easily. Yoda's wisdom, coupled with his amazing defensive abilities, coupled with Malak's unimaginative, predictable style, make this a short fight. 10 minutes (15 if on Star Forge)
Sidious defeats Windu. This one took the most thought. Sidious doesn't have to worry about turning Anakin here, but also Windu doesn't have to worry about arresting Palpatine so he can just be focused on destroying an evil and not-saveable opponent. I give the edge to Sidious bacause of the power of his lightning, and poor Mace just doesn't understand the nature of the Force deeply enough to repell it for long. 10 minutes
Vader defeats Kenobi easily. Do I even need to talk about this one? 10 minutes
Tyrannus defeats Jinn easily. Dooku has a deeper understanding of the Force as it relates to combat. Jinn uderstands how the Force relates to life better than perhaps anyone, but his lightsaber technique is much to open compared to the efficiency of Dooku's style. 10 minutes-or-15 minutes with a lot of dialogue
Shan defeats Maul. I expect this one to spark some debate, and I admit a certain bias. Also, I need Shan for the next part.
30 minutes of Shan barely holding on, then winning with a cheap shot, like dropping Maul off of a walkway or into a core shaft.
After Sidious defeats Windu, knowing he needs rest before another confrontation of that magnatude, announces that he is going to allow his comrades to defeat the remaining jedi, and then they have to fight to see who will be his new apprentice.
Now having their own choice of fights:
Shan vs. Revan
Vader and vs. Yoda
Tyrannus
Bastila defeats Darth Revan. Obviously, Shan is no match for Revan's skill with a lightsaber, and Revan is much more powerful than Bastila in the Force. So what am I thinking? Bastila's compassion will win Revan back to the Light. Sort of a returned favor. 5 minutes
Yoda and Dooku defeat Vader. I kind of gave this one away already. Yoda would turn Tyrannus back to the Light (a la Dark Rendezvous), and then they would easily defeat Vader. 5 minutes
Sidious, now horribly outnumbered, tries to run.
The jedi, being jedi, let him go.
The cycles repeats twenty years later with different characters.
Yoda can only fight for 6 minutes max cos he has to use the Force to help him move so if any one could hold him off for that time it would be curtains for yoda.
i hav 2 ideas
Ani v dooku
obi v maul
mace v sidious
qui gon v malak
yoda v revan
luke v vader
in this 4 of the fights hav already taken place, so ani, obi, mace and luke would all come out winners. Qui gon cud hold off malak until support came, but lets say he died. Malak would go to revan and yoda and work yoda to the limit until the rest came. ani and obi take malak off and do there special tactics that would defeat him, whist revan has yoda, mace, luke on him. this ends with a jedi win.
the other is
luke v maul and dooku
malak v obi and ani
yoda v sidioius and vader
revan v mace and qui gon
obi and ani would win in 2 mins and split up 2 help yoda and luke, revan and mace and Qui gon would carry on. yoda and obi would beat sidious and vader and luke and ani would beat maul and dooku.
.......Wow.
True, Yoda uses the Force to jump around and everything, but that doesn't mean he could only last for a few minutes. And I suggest you watch the movie again, Pink, because Yoda was matching Sidious blow for blow until Sidious started throwing Senate Pods at Yoda. In a straight out battle, Yoda would have won. But this battles far too large, I'm not typing everything there is to say about it.