Jason and the Argonauts (1963)
It's filled with Ray Harryhausen's stop-motion creations, as well as other remarkable effects. To me, this is Harryhausen's masterpiece. While the skeleton battle is considered to be the most difficult stop-motion scene ever filmed, my favorite is their encounter with Talos.
I LOVE the go-motion dragon in "Dragonslayer"! In fact, Vermithrax pejorative is my favorite dragon of all time, far better than the average CGI attempt though "Dragonheart" is rather good.
In "Krull", my favorite part is the Crystal Web spider, one of the most realistic-moving spiders in cinema history. I HATE spiders, but it's so elegant and beautiful that I'm fascinated every time I view this movie.
Very few CGI scenes impress me, but I continue to love these films:
Legend
The Dark Crystal
King Kong (1933)
The Thief of Bagdad (1940)
The Golden Voyage of Sinbad
Sinbad and the Eye of the Tiger