[Fingolfin II]

I'm inclined to agree with Boromir here. As far as I know, Saruman's ring was only mentioned once in the whole entire story and that was when Gandalf spoke about their encounter to the Council of Elrond. Gorthaur, you have overlooked the fact that Sauron was the one who created the Uruk-hai; Saruman just experimented. Besides, if the ring was such a big factor in the story as you suggest, I'm sure Tolkien would have mentioned it more than once. To my mind, the Ring was more of an example of Saruman's former wisdom being replaced by arrogance and his attempt to copy Sauron in the hope of sharing some of his power.

Saruman deeply studied the lore of the Great Rings, but whether this was enough for him to actually replicate the power of a Great Ring is doubtful. I mean, even the grandson of the greatest Elf-smith ever probably couldn't have forged the Great Rings with such potency as they contain without Sauron's instruction.

As Boro said, it is not entirely known about the origin of the Uruk-hai, though it is likely there was cross-breeding between Men and Orcs. This is supported by a quote said by Gandalf somewhere in LotR, as well as by a discussion between Pippin and Aragorn in Isengard.