I actually think ET is one of the great movie scores. But at this point, who would notice anymore when composers lift wholesale from the classical tradition? Perhaps (and no more than perhaps) it's a blessing in disguise. It's like that quote I read on twitter sometime ago:
"Bad writers borrow, good writers steal, great writers kidnap, Shakespeare ran a death camp."
In any event, everyone should hear the extraordinary piece upon which it's based, Dvorak's Dumky Trio. I'll link to the whole piece below. But if you're in the mood to listen to some of the most beautiful music ever written, go to 12:30.