Smeagol had the ring for nearly 500 years and never completely succumbed to its power like the ring-wraiths did. While he was corrupted, he still had a spark of himself under all those centuries of madness. I believe Gandalf specifically points this out somewhere. Something about the nature of hobbits enabled them to resist the ring better than any other race, even the high elves that had lived on Valinor–heck, even Gandalf, a Maia, feared to take up the ring. The only person who seemed able to bear it with no corruption was Tom Bombadil in the books.
Smeagol had the ring for nearly 500 years and never completely succumbed to its power like the ring-wraiths did. While he was corrupted, he still had a spark of himself under all those centuries of madness. I believe Gandalf specifically points this out somewhere. Something about the nature of hobbits enabled them to resist the ring better than any other race, even the high elves that had lived on Valinor–heck, even Gandalf, a Maia, feared to take up the ring. The only person who seemed able to bear it with no corruption was Tom Bombadil in the books.