First of all, thank you
Boromir for pointing out my error. I think I was mixing book and movie again.
I do agree with
davem on his point about Sauron increasing in power. He was currently on the verge of conquering the last major resistence when his Ring was destroyed.
And I also really like what
Boromir said about Sauron and the Ring having a 'Master-Master' relationship. It occured to me that really one cannot master the other, insomuch that they are the same. They have one will, even though the Ring seems to be more important to the survival of both.
Maybe Sauron made a mistake putting so much power into the Ring. Perhaps he could have acheived the same abilities (more commanding influence, power over other Great Rings, etc.) without putting so much of himself into the little blighter. It would have ensured that he would still have most of his power without it and kept him from being linked to its survival.
But already I can see that not working. Without putting so much into the One, he probably wouldn't have gained influence over the other Rings. Also, if the Ring had a less commanding will, it could be taken from him easier. Another might be able to master it, and then really use it against him.
Yet here's an even better thought. Perhaps he put so much of himself into the Ring that if it were ever lost(as it was) it would conquer its bearer and eventually find its way back to him(as it almost did!). That would make sense, since I've heard that the greatest fear of those who have power is losing that power. He was afraid of losing his Precious, and so made it so powerful that it was it's own saftey mechanism.