The Inherent Incompatability of Morgoth and Sauron

[Inziladun]

To me, the sin of Morgoth and Sauron is practically identical: each believed his version of "order" to be superior to that established By Ilúvatar through his servants, the Valar. Though Melkor merits a greater penalty for being the prime corrupter of the efforts of the Valar, Sauron's telling error was his inability/unwillingness to humble himself after the fall of Morgoth. That should have been a red flag to him that his road was a dangerous one that would lead him to ruin. Pride in the memory of his power under Morgoth filled him though, and pride led him to think he could order the world to his will despite his much greater master being proven incorrect on the same assumption.
It is my belief that anyone can make a mistake, and I don't fault Sauron so much for his initially following Morgoth. What I do criticize him for is his failure to repent when given the chance. Saruman's later fall is a result of the same arrogance and lack of humility.

Originally Posted by Boromir88

Later, Morgoth spun downwards into nihilism, and Sauron never reached this stage of chaos, since he still had, what Tolkien calls "relics of positive purposes." I think, given enough time Sauron was following down the same path and would have become a nihilist

I think Third Age Sauron was at the nihilistic point. Whatever had originally guided him to try and make the world his own he had lost sight of, blinded by the prospect of simply having power and control. A world of Orcs and evil men was not his ideal: he preferred to enslave the West. It was not then enough that lesser beings did his will. They should be made to do it against their own.