Gonna try and jump-start this once, see if it sticks.
I remember being stunned, when I first watched DS9, at all the little differences between the way Starfleet and Cardassian technology sounded. Cardassian transporters powerful--quite a lot of bass kick, like they had a lot more juice coming to them than the Federation ones.
But the really telling thing, to me, was the "red alert" sound. This was before I'd ever heard anything from the Federation besides the typical earsplitting TOS/TNG siren that seemed like it had to degrade readiness more than stimulate it.
The Cardassian version was so...NOT obnoxious. I remember thinking, even though at that point I was WAY more a Borg fan than Cardassian, something like, Hey, these people have some SENSE!
Overall, I just find the Cardassian sound scheme far less obnoxious and/or silly-sounding than its Federation counterpart.
What about any others? Any other sound effects that struck you as particularly cool? Which do you think you would find most livable on a daily basis?