[Ainaserkewen]

Hmm, Kuruharan, seems I've misplaced some of my ideas, eh?

Morgoth wanted domination. He believed that the lands of Middle-Earth should be his and his alone because he participated in their making the most. He destroyed the creations of the other Valar because of jealously and probably pride.

Sauron was not competing with his peers, he surpased them not in power but in ingenuity. He used the vast ressources of Elves and Men to conquer, for example the Ring. It is my belief that because he was losing his hold on the lands abandoned (so it seemed) by the Valar, his thoughts would have went to most drasic plans then previous. Sauron was challenged by Elves and Men and wiping out light would certainly cripple them. Perhaps that wasn't his plan, but the fear that he could spread with his whispers and silent orders was a good start.