Not only is this movie fun and corny as hell, but the music in it is so great; most of the tunes are wonderfully catchy! Anyway, my favorites are:
"Touch-A, Touch-A, Touch Me" - The moment in the movie near the end of this song where Magenta and Columbia are rolling around together and laughing hysterically is the single greatest moment in the whole flick.
"Eddie" - I think it is impossible NOT to sing along to this!
"Super Heroes" - Hard to believe that the bulk of this song and the movie footage was not included on the original U.S. release. The crescendo at the end with the harmonies is incredible.
"The Time Warp" - An obvious pick, but this song rules. A girl friend and I always do this song whenever a bunch of us go out to karaoke, or if we go to a wedding reception where it is played, singing and dancing and all.
"Rose Tint My World" - The whole long sequence ending with the "I am a wild and an untamed thing" is a major highlight. Gotta love the "Don't dream it, be it" section.
Plenty of other good ones, too, including the "You Better Wise Up, Janet Weiss" tune, which isn't included on the soundtrack, but is in the movie.