What do you think was the most Important battle in Middle Earth? I have been trying to work this out for a few days, and can't decide from

-The Disaster of Gladden Fields [The Ring is Lost]
-Battle of the Last Alliance [Sauron loses the Ring]
-Battle of Pelennor Fields. [Death of the Witch-King, Theoden and allows the Battle of the Black Gate, which allows Frodo to destroy the Ring]

and Possibly the battle of the Black gate, which allows Frodo to destroy the ring. What do you think was the most important?

Exactly, but Isildur losing the Ring allowed it get passed down to Frodo, instead of staying on Isildur's mantelpiece allowing Frodo to eat scones, and possibly meaning it doesn't get destroyed.

Getting it away from Sauron was important, but Isildur didn't destroy the ring. He could have done anything with it, and was going to leave it on his mantelpeice, until he got killed at Gladden Fields and lost the ring.

The Most important battle for anyone, like if there was one that allowed Sauron to be king of Middle Earth and turn everyone into Orcs, or one that allowed Aragorn to overthrow middle earth, and replace all the orcs with humans again.

I have to agree with Sian, the Last Alliance. If Sauron would have survived with the Ring, who knows what would have happened.

Well Gimli, if the Valar hadn't unleashed their power against the First Dark Lord, things would have been far worse! Morgoth was the First Evil, a Valar himself, far more powerful than Sauron his lieutenant. No battle from the Third or Second Ages could possibly compare to the Nirnaeth Arnoediad or the War of Wrath.

I've read the Silmarillion (after a hard struggle), so I have some knowledge.

Basically the War of Wrath was when Earendil (father of Elrond, actually a man and why Elrond was called half-elven) sailed across the Western Sea from Beleriand (land north of what we classically think of as Middle Earth - Arnor, Rhovanion, Rohan, Gondor and Mordor. The Ered Luin or Blue Mountains were actually much longer at the time, stretching all the way north and through Beleriand) with a Simaril (one of the three incredibly beautiful jewels that Morgoth stole from the Elves living in the Undying Lands, causing one of their 'clans', the Noldor, to travel over the Sea and fight against him. The one that Earendil had was actually stolen from Morgoth by Beren and Luthien) to light his way. He came to the Undying Lands and begged the Valar (basically the Gods of Arda) to destroy Morgoth (because by this point most of the Elves had been killed or corrupted). Once they had heard the whole tradgedy, the Valar went across the Sea (in wrath) and destroyed Angband, the land of Morgoth, and his vast and ancient fortress there. Such was the power of the Valar that they submerged Beleriand beneath the Sea, causing the end of the First Age.

Thanks. Were the 3 Silmaril turned into 3 Rings of power?

Well, Fornac, I never have been able to read the Silmarillion, but I have read most of the Unfinished Tales, so I am ill-informed of most other battles.

One of the three Silmarils was thrown in the ocean by Maglor; one went into a fiery abyss with Maedhros; and the third sails through the nighttime sky on Eärendil's brow.

The Silmarillion is only confusing because it contains so many names and covers thousands of years. Take it a little at a time and use the info at the back of the book to see the genealogies of the Elves and the first Men. And no one learns it all in one reading, so don't worry if you get bogged down in the Creation story and all about the Valla; you can come back with a later read to get a better understanding. The book's first bad guy, Melkor (Morgoth) was later Sauron's boss and predecessor; and he was ever so much worse than Sauron, having Dragons and Balrogs, besides Orcs and Trolls at his command besides Orcs and Trolls at his command, he had .

My proofreading editor fell down on the job with that one, eh what?

Must have been another of my senior moments.

  Now let's not forget the battle of the Shire, it may not have been the most important, but the old man never stood a chance and it was of great importance to the Hobbits, a whole life and lives of further generations, why, Rosie Cotton would never of had her baker's dozen of buns to continue Samwise's line if they were beaten

I must disagree.  No battle with Sauron was child's play.  And all battles throughout the Ages were important and had far flung revocations.  The defeat of Sauron by the destruction of the Ring was brought about by several incidents that had weakened him in the past.  He fought one on one as the greatest werewolf with Finrod Felagund and though he brought about Noldor prince's doom, he also had to use his spirit form (since he was a Maia) to tuck tail and run back to the feet of his master, Morgoth the Thief, to lick his wounds.  His lust for power and spite for the Children of Illuvator always led him to acts that led to his downfall.  By putting forth his power in the One Ring, he once again weakened himself and made his eventual doom possible.  Remember he fooled Celebrimbor into thinking he was fair and giving his knowledge freely.

I do agree and am most saddened that the Nirnaeth Aernodiad was the most triumphant moment for the Evil of the North.  That battle was so important in several ways.  First, we must remember that some Men turned on the side of good and turned the tide of the battle for Evil.  But that defeat set up the eventual end of the War of the Jewels when Hurin and Hour saved Turgon, thus setting up the eventual mergence of the races and birth of the greatest mariner to sail MiddleEarth.

The Silmarillion may be hard to digest for many, but I STRONGLY urge anyone that puts it down to pick it up again after a while.  It brings so much more to the tales of later years and gives the reader much more insight into the plight of the Elves.  I mean, if you haven't read TS, you don't really know why the Elves go into the West or where they are going to. 

I know I strayed from the battle theme but it all came in a rush and I would love to discuss any of the many battles in ME.