I was on the Leaked GB (unrooted) version and when I installed and run the Netflix app, it would do everything short of actually playing the movie. Today, I sbf'ed back to stock froyo and thought I give it a try again. I used the same apk file that I downloaded while on GB and installed it once sbf'ing was complete and it seems that the movies r playing on the X now. The apk file I used is from Dowload Link 1 (netflix-devicecheck-disabled
Netflix Removes Device Check, Should Work on Most Android Devices (Updated) - Droid Life: A Droid Community Blog
This link works on my just updated Droid X .
Love my Netflix