I like the X and think it should stay X. I pronounce it OS TEn not OS EX as I used to. I think it should stay that way because it signifies a new era in apple computing.
I was so shocked when I upgraded to X from 9. Apps still quit but it made freezes virtually obsolete even on my 350 mhz G3.
Maybe just call it OSX in genaral and then just refer to the Darwin version when specificity is needed.
OSX, darwin 8.x
EDIT: I think we should email this thread to Apple!