The music played as Krypton begins to shake apart, and Jor-El launches the ship containing his son. This was later reprised in a Justice League episode, when Superman was in a fantasy Krypton with a son, as said Krypton began to fall apart as Superman realised the illusion.
The fourth episode of the series, "A Little Piece of Home", which introduced Kryptonite, had an unnamed, one-off villain with a jet pack. He and his crew had a completely kickass neo-50's theme that was only used for that episode.
Lobo's episode, "The Main Man", had awesome metal play whenever he was onscreen.