How should I configure my Audio settings for the highest quality sound?
48000Hz is more than adequate for the audio range as there are not going to be any pre-recorded formats above this, and the human ear can only hear around 20000Hz anyway. CDs are only 44100, most DVDs now are at 48000, and while BluRay supports 96000 it's unlikely the audio is actually recorded in that quality.

24bit integer vs 32bit float is actually the same quality, the 8 floating bits on the later are for other things which generally come into play with music production I believe.