The answers (in order recieved):
But my answer has to be "Leprechaun 4: In Space." It has just the right amount of bad to maximize its interest/amusement value. Even the gratuitous nudity is amusing ("this is your death"). The juxtaposition of leprechaun with space marines & alien princess is inherently amusing. It avoids the cardinal sin of bad movies (though shall not bore), and of course, Warwick Davis! Doing a John Wayne impression....
Let's face it, Rocky I was excruciatingly slow, good, but slow. Rocky II was a bit faster, but still slow by today's standards. Rocky III and IV really picked up the pace, and that's when I hopped on board as a youngster. Apollo was a good guy, but Clubber Lang and Ivan Drago were comic book villains. My brother and I absolutely ate it up. It was almost like the movie was made for kids. They kept the mushy Rocky-Adrian stuff down to a minimum and the spectacle to a maximum. I'm 26 years old, I double majored in political science and history, and yet the first thing I think of when I heard the old Soviet anthem is that scene in Rocky IV when Drago enters the arena in Moscow.
Runner up: Top Gun. Great flying scenes, hammy performances and cheesy dialogue. It probably set the tone for future Bruckheimer movies, but before it got old. It followed the same track as Rocky IV, cartoonish villains (also known as "the enemy" and their "MiG-28s,") memorable yet cheesy dialogue, over the top bad acting, and a spectacular soundtrack.
Honorable mention: Universal Soldier. Dolph Lundgren and Jean Claude van Damme are involved, need I say more? This is easily the greatest Van Damme film ever made, which is either saying a lot or not saying a lot. Van Damme makes Dolph Lundgren look like Laurence Olivier.
And yes, I own all three on DVD.