As expressed by Gollum, Sauron has a physical form. Voldemort, without the Ring, could probably sneak into Mordor, and his feats could well be sufficient to defeat Sauron. But while the One exists Sauron can not be vanquished permanently. He would return, and Voldemort is the perfect enemy for him to defeat.
Another thing to mention is that Sauron has bested multiple wizards before like Saruman or Gandalf, meaning that he'd eventually beat Voldemort in the end, though the Avada Kedabra could most definitely kill him. Boomstick: If you think Voldemort stood a chance, you'd be Saurong. Wiz: The winner is Sauron.
Dumbledore could not have beaten Sauron in combat for the same reason: He lived in a world of humans, not immortal beings of immense spiritual power. His spells were not the right sort. However, he did have one ace in the hole that would have made the whole enterprise far easier: the Fidelius Charm.
Voldemort has Legimency, Palpatine has Precognition. Voldemort has Horcruxes, Palpatine has clone bodies. Voldemort has Killing Curses, Palpatine has Force Lightning. Voldemort can fight multiple high-level foes at once and win, so can Palpatine.
Voldemort has way more combative magical feats than Saruman, but the few that Saruman has in books and movies are greater than Voldemort's, in terms of overall magic. Voldemort split his soul to gain immortality. Saruman is born with it.
Without a doubt, the most powerful wizard in Middle-earth is Gandalf the White. While Gandalf was always a reasonably powerful wizard in his own right, facing off against the Balrog in the Mines of Moria, a battle that took ten days and resulted in the mutual demise of Gandalf and the Balrog.
Like Tom Marvolo Riddle (aka Voldemort), Merlin was a Slytherin, an ambitious, powerful wizard. He was a wizarding legend, and, of course, more powerful than the Dark Lord. According to the Harry Potter Wiki, Merlin was “arguably one of the most powerful wizards of all time”.
We would have to give the victory to Darth Vader. While the two dark lords seem perfectly matched on their villainy and power, Darth Vader's lightsaber and ability to immediately use the force to choke Voldemort, without chanting any spell would end this showdown in seconds.
1 Luke Skywalker
Having faced his father once before, Luke was familiar with his tactics and used the force to gain an upper-hand. In Star Wars Canon, only Luke Skywalker can be acknowledged as the one who truly defeated Darth Vader.
Finally Sauron came out to fight Elendil and Gil-galad face to face. When Elendil fell, his sword Narsil broke beneath him. Isildur took up the hilt-shard of Narsil and cut the One Ring from Sauron's hand, vanquishing Sauron.
Morgoth Was Originally More Powerful Than Sauron
When he couldn't accomplish that, he began to war against the other Valar and rule over Middle-earth with his fires and evil creations. With this turn to darkness, Melkor became known as Morgoth.
However, the mere fact that the Valar didn't prioritize perusing Sauron proved he was a much lesser threat than Morgoth. It made perfect sense because Morgoth was a Valar, and Sauron was only a Maia. So, while Sauron was evil, Morgoth was clearly much worse.
Would Sauron be able to taint and subsequently command Elrond, Galadriel and Gandalf through the use of their own elven rings, like he does with the Ringwraiths? In theory, yes. It would be possible for him to control them using the ultimate ring of power, in the same way that an alpha wolf controls its pack.
Admittedly, the Witch King takes some power from Sauron, but of necessity it is less than Sauron himself possesses (which may or may not be enough in its entirety to destroy Gandalf the White, but definitely is not when only a fraction is brought to bear).
Sauron would most likely win in a fight against Darth Vader because he is basically a god or angel-like being with powers that far surpass what humans are capable of.
Yoda will most likely win in a fight against Darth Vader because he is more skilled with a lightsaber and has the experience and feats that allow him to trim whatever size and strength advantage Darth Vader has over him. In fact, Yoda nearly defeated Palpatine, something that Vader could never do.
Master Yoda has risen above all others to claim the top spot as the most powerful Jedi of all time and the true chosen one according to IGN's audience. He won pretty handily as well, as he was victorious in 89,756 of his 95,243 battles and had a win percentage of 94.2%.
This might be a bit of a controversial pick at just number three, but Darth Vader, perhaps the best-known Dark Side user, is not the most powerful Sith ever. Born Anakin Skywalker, Vader became an extremely powerful Jedi Knight, one who was prophesized to be the "Chosen One" who would bring balance to the Force.
There's not a person in the Star Wars lore that can beat the Hulk. You could throw every Sith Lord and beings with the force his way and they'd all lose. One by one or all at once, the Hulk would beat them all. You can take your pick with which Hulk Darth Vader fights.
As Darth Vader, Skywalker was believed to have had roughly eight-tenths of the strength of the Emperor. Nevertheless, Vader wielded tremendous power and skill, enough to use the Force to overpower almost any opponent he could not defeat with his lightsaber.
Besides Dumbledore, he is also the only wizard ever known to be able to apparate silently. Voldemort was also said to fear one wizard alone, Dumbledore.
Arguably more hated and more dangerous than Voldemort himself, there are many reasons why Dolores Umbridge is the most hated Harry Potter character. Dolores Umbridge was arguably the most evil character in the Harry Potter series, sometimes more so than Lord Voldemort, mainly Harry Potter and The Order of the Phoenix.
The Horcruxes Left Him Vulnerable & Weak
Although they did give Voldemort another chance to join the living after his curse against Harry Potter rebounded, they harmed him in the long run.