That, and Shiro Kazami/Rider V3, while surrounded by fire, using a Rider Punch on his own, horribly mutated sister to fulfill her wish to die rather than live in pain.
Kamen Rider (1971-1973)
The first fight Kamen Rider 1 has with Kumo Otoko and the Shocker foot soldiers. Really got to hand it to the stunt work there, especially for a first episode.
Episode 2's night fights against Komori Otoko and Shocker's combatants.
Episodes 6 and 7. Full stop
Episode 13, where Kamen Rider #1 beats up EVERY SINGLE Shocker's Inhumanoids that appeared thus far. There's a reason this episode was adapted into a movie.
While filming for episode 10, Fujioka Hiroshi got into a motorcycle accident - footage prior to the crash was used in the episode. (He apparently remembers up to the point where he took his leg, badly twisted out of position, and realigned it.) This put Rider #1 out of commission, while Rider #2 took over beating the crap out of Shocker. Several months later, Fujioka recovered and returned to the show - and thus the Double Riders were born.
Hayato's debut episode. All of it.
The awesome final showdown between Pirasaurus and Kamen Rider #2 in episode 17. Even to this day the fight choreography holds up pretty well, especially for it's time.