[Boromir88]

When Smeagol killed Deagol, it wasn't because the Ring amplified his personality; it was because he was possessed with an overpowering desire for it, and Deagol stood in the way.~Rikae

I think that's the main point where we disagree (which isn't a bad thing ).

The thing is, I don't think the Ring creates any sort of different feelings within anyone. It uses what the person is already like, and what is already within the individual.

As an example with Bilbo, he is a good-natured, well-intentioned hobbit, with really no signs of wanting to commit evil. You are right, in that the circumstances one acquires the Ring are very important about the effect of the Ring. And Bilbo getting the Ring out of his pity for Gollum is a tribute to Bilbo's character as a person. He wasn't a violent/weak-minded person. He was a good-natured, caring hobbit.

Also, the example I gave with Boromir, where the Ring plays with Boromir's desires of Victory for his country and his own glory with it. The Ring doesn't create these feelings within Boromir, they are already there, and the Ring uses that to it's advantage. As Faramir notes:

I can well believe that Boromir, the proud the fearless, often rash, ever anxious for the victory of Minas Tirith (and his own glory therein), might desire such a thing and be allured by it.~Window of the West

The Ring uses the desire for his own glory that is already within Boromir to get Boromir tempted and eventually attempt to take the Ring from Frodo.

Let's take the Ring tempting Sam for another example:

He felt that he had from now on only two choices: to forbear the Ring , though it would torment him; or to claim it, and challenge that Power that sat in its dark hold beyond the valley of shadows. Already the Ring tempted him, and he saw Samwise the Strong, Hero of the Age, striding with a flaming sword across the darkened land, and armies flocking to his call as he marched to the overthrow of Barad-dur. And then all the clouds rolled away, and the white sun shone, and at his command the vale of Gorgoroth became a garden of flowers and trees and brought forth fruit. He had only to put on teh Ring and claim it for his own, and all this could be.~The Tower of Cirith Ungol

That's what I mean with the Ring playing with the very nature of the individual. Is it any coincidence that Sam is a gardener, and the Ring says puts me on and the Gorgoroth will become a great and splendid garden at your command? The Ring uses the very desires of the individual, and plays with their nature.

So, Gollum's murdering for the Ring only shows his weak-mind in that he couldn't resist it upon seeing it. But, my point was that the way he uses the Ring is a great insight to what Smeagol's character was like before he came across the Ring.

To an extent you are right, eventually the Ring will make people do things that they would not have initially done...as you show with Bilbo snapping at Gandalf upon asking for it. But, good-natured and strong individuals don't feel this effect from the very beginning. As Gandalf mentions:

"But I have so little of any of these things! You are wise and powerful. Will you not take the Ring?"
"No!" said Gandalf, springing to his feet. "With that power I should have power too great and terrible. And over me the Ring would gain a power still greater and more deadly." His eyes flashed and his face was lit as by a fire within. "Do not tempt me! For I do not wish to become like the Dark Lord himself. Yet the way of the Ring to my heart is by pity, pity for weakness and the desire of strength to do good...."~Shadow of the Past

Eventually Gandalf realizes the the Ring would make him more like Sauron, over time. However, the way of the Ring, what the Ring would do to accomplish that, is to use Gandalf's pity and desire to do good.

The Ring uses already what is in the individual to get control of them. It brings out their greatest desires and makes them believe, claim me and it so shall be.

Gollum's murdering of Deagol speaks to his weak mind. But what Gollum does shortly after he gets the Ring shows the nature of Gollum even before he came across the Ring. We know before Smeagol came across the ring he was a 'mean soul' and that further is shown with the way Smeagol uses the Ring for malicious intent and thieving upon getting it. The Ring didn't create these desires, or actions in Smeagol, they already were there. The Ring just brought it out of Smeagol and made Gollum (the thieving, the just overall 'evil' already dormant within him) the dominant factor.