I had less of a problem with Data sacrificing himself than I did with the writers cynically leaving the door open for Data Mk. II in B4.
Oooooh, me too. When I heard "someone" dies in NEM, before the movie even opened, I immediately suspected Data - because he's the cheap cop-out death, the one character who could be resurrected by far the most easily.
And then they trotted out his replacement early in the movie, and I felt like vomiting. Sure enough...
That whole scenario just encapsulated how chickenshit and cynical Berman Trek had gotten. And I love
Data! (Look at my frakking avatar!) I couldn't believe they could kill him off in a way that had me feeling nothing but contempt and annoyance.