Gormenghast was probably the first thing I saw him in when it aired here in the States on PBS in the summer of 2000. Right around that same time I read an interview with him in SciFi magazine, talking about his career and that he was playing Saruman in LotR. I think by that point it was known he had a role in the as-yet-untitled Episode II, a role not dissimilar from his Hammer cohort Peter Cushing's in Star Wars '77.
I remember finding it pretty mind-blowing that a guy pushing 80 was taking on such big roles in these huge franchises.
It wasn't until later that I saw his earlier work, like The Wicker Man and The Man with the Golden Gun, although I still haven't actually seen any of his Hammer/Dracula stuff (must rectify this soon).
How cool that he was able to reprise his role of Saruman for The Hobbit.
What an extraordinary life!
He will be missed.