That's a huge loss to composing, and music in general.
Chariots was an important film for my mother, and Blade Runner a seminal film for my father (for reasons not relevant to this thread), so Vangelis has always been a celebrated name at home. His Chariots of Fire theme is a fantastically evocative piece, you can almost feel each step being run by Liddell as he powers forwards.
But I'd maintain that Blade Runner is his crowning glory. He conjures up entire worlds, with that ethereal blend of synths and brass and jazz. It's just as much a hodgepodge of new and old as the setting of the movie, and does more world-building for the film than perhaps any of its sets.
Feel obliged to link to the original Tears in Rain sequence. Given the semi-improvised dialogue, Vangelis did an incredible job of matching the sense of uncanny fear, trepidation and then grief/regret that the film is going for:
