Aliens exist, though Roswell and Area 51 may not be involved. Its really a mathematical certainty that life exists somewhere else. In our solar system alone we have several moons or planets that either have water, or could have held water at some point. Thats out of 8 planets, 1 pluto, and numerous moons. Multiply that by however many billions of suns there are in the universe and theres simply no way we're the only planet with life. Now have these other life forms visited us? I have no idea. There seems like tons of evidence, but who knows? Theres a lot of evidence of alien technology aiding with ancient civilizations. But why and when did the aliens stop helping us?
The Illuminati and Free Masons exist, though I doubt they have as many dark secrets as has been portrayed in movies.
Moon landing possibly a hoax especially given the time period. It was a big way to show superiority to the USSR so there would have definitely been motivation.
9/11 not a hoax. If you believe in the conspiracy theories then you have to believe the incredibly incompetent Bush administration pulled off one of the greatest tricks of all time. And to be honest I haven't heard a single theory that hasn't soundly been proven wrong.