which is the best?
What are you trying to accomplish?
None of the above, the best approach is the dialectical method. The four concepts you present are related as false alternatives.
First, is the false alternative of dualism vs monism. The dualist looks to extreme poles for truth, the monist looks to emphasize one opposite at the expense of the other. Both methods are dead ends if used in isolation. In contrast, the dialectic thinker embraces rational aspects of both dualism and monism and looks to common roots of the apparent opposites. She differentiates and integrates a topic and presents an alternative view that transcends both of the opposites. At times, she may embrace parts of each opposite, at times reject both and move to formation of a new idea.
Second is the false alternative of idealism vs materialism. The former holds there to be consciousness without existence, the latter holds there to be existence without consciousness. Both views are false. Idealists are modern day conservatives, materialists modern day liberals. Again, the dialectical thinker seeks to find common roots within the opposites--she thinks to integrate.
Hegel puts in a nutshell the dialectic approach of thinking: "The Truth Is The Whole".
None, Radical Glee-Ful Nihilism Baby! WHOO!
Why? Because "It's Funny" is just as good a reason to do anything as anything else.
Separate names with a comma.