@AC - Rocky Horror - musical - no debate (Tip - just because someone is, or claims to be, an alien in a tale does not automatically make it SF. Indeed, most stuff that Hollywood, TV and the theatre call SF is actually either Space Opera or pure Fantasy). Flash Gordon - Space Opera - also no debate, whether you're talking about tehoriginals I recall from childhood at the cinema, the film with Brian Blessed as a winged man, or the TV series with the irritating wee robot for comic relief, and also fantasy in teh case of the former two.
What? No, I don't need a glass of water, thank you, the shuddering will stop in a few minutes, it's just my OCD over genre categorisations giving me the twitches.. :-}