Boromir's perspective
Understanding Boromir's motivations
Let's talk about Boromir. Son of Denethor, Captain of Gondor. On first viewing/reading Boromir comes across as power hungry and the member of the fellowship most likely to be be tempted by the ring. However Boromir isn't just some power-hungry jerk who tried to steal the Ring. His motivations are sound. His actions make sense.
Why does Boromir act the way he does, why is he the one most tempted by the one ring?
Boromir first makes his entry into Lord of the Rings when he utters the immortal words.
One does not simply walk into Mordor. Its Black Gates are guarded by more than just Orcs. There is evil there that does not sleep and the Great Eye is ever watchful. It is a barren wasteland riddled with fire, and ash and dust ... the very air you breathe is a poisonous fume. Not with ten thousand Men could you do this. It is folly.
And what if we fail, what then? What happens when Sauron takes back what is his?
Boromir is from Gondor
To state the obvious, Boromir is from Gondor. If you pull up the lord of the rings map, Gondor shares a border with Mordor. So when he sees a way to destroy Mordor once and for all he obviously wants to take it.
"Why not use this Ring?" [paces] "Long has my father, the Steward of Gondor, kept the forces of Mordor at bay. By the blood of our people are your lands kept safe! Give Gondor the weapon of the enemy. Let us use it against him!"
Boromir longs to restore peace to Gondor from the menace of Mordor.
My father is a noble man, but his rule is failing, and our ... our people lose faith. He looks to me to make things right ... and I would do it, I would see the glory of Gondor restored. Have you ever seen it, Aragorn? The White Tower of Ecthelion, glimmering like a spike of pearl and silver, its banners caught high in the morning breeze ... have you ever been called home by the clear ringing of silver trumpets?
Skin in the game
Boromir has skin in the game. Unlike the others, for whom Sauron exists as an Abstract Baddie that is out to get the ring, for Boromir, Sauron is an evil is right outside his front doors. He is paranoid about taking the ring straight to Sauron’s and for good reason. Once Sauron has the ring, he will be unstoppable.
Consider also that Aragon is a wanderer and never been to Gondor for years. Legolas has the option to leave Middle Earth. The dwarves can hole up in their caves and the Shire is far away. The hobbits have never suffered the way men have suffered under Sauron. Only Gondor and Rohan see the threat of Mordor daily. For Boromir, this is no mere quest.
The ring tempts Boromir
The ring which knows the inner being and wants of every human in it’s vicinity uses this to tempt Boromir. The ring whispers to him that they are taking the one ring that Sauron most desires straight to him. The ring whispers to him that the halflings will fail and that Gondor will fall. The ring whispers to him and tells him to take the ring and use it to destroy Mordor and Sauron.
I see your mind ... you will take the Ring to Sauron. You will betray us! You go to your death and the death of us all! Curse you! Curse you and all your Halflings!
Boromir’s a man caught between a rock and a hard place, with Sauron breathing down his neck and the weight of Gondor on his shoulders. In the end, Boromir fought off the temptation of the One Ring. He died protecting the hobbits. He recognized Aragon as the true king of Gondor.