I've been on a kick with this kind of movie. Recently I've watched The Parallax View and Three Days of the Condor. I suppose Michael Clayton loosely falls in this category too. The Conversation and All The President's Men are some more great ones.

For some reason, I love the conspiracy stuff. I'm a level-headed guy, but it really intrigues me (JFK is one of my top ten favorite films). And of course, I'm excited that a second X-Files movie is going to be made.

What are some other films in this vein that are good? I plan on watching Klute soon, but would like some other recommendations.

I think one of my favorite Brian DePalma films, Blow Out, falls into the category.

Z, Coma, Touch of Evil, The Lady From Shanghai, the original Stepford Wives and about half of Alfred Hitchcock's films.

I always thought Cube was an underrated film. The acting isn't great, but for a low budget thriller, it's pretty original and EXTREMELY paranoid.

Also: The Manchurian Candidate, my mom's favorite thriller and a paranoid one. In a light comedy, The President's Analyst. My favorite JFK conspiracy flick, Executive Action. More recent paranoid flicks Revolution #9 and Fabled, are at least worth watching when they show up on cable.
Can't forget Dr.Strangelove either.

I just want to make it clear, crazed, that you're talking about the original The Manchurian Candidate (1962) with Frank Sinatra, Laurence Harvey and Angela Lansbury.

Definitely the original The Manchurian Candidate. The remake was unneeded and unnecessary. And mama crazed wouldn't have anything to do with it.

My top movies with the highest amount of paranoia content.

Enemy of the State (1998)
The Bourne Identity trilogy (2002, 2004, 2007).
The Da Vinci Code (2006).
Fahrenheit 451 (1966).
A Beautiful Mind (2001).
The Thing (1982).The Day the Earth Stood Still (1951).
The King of Scotland (2006).
Invasion (2007).
House of Mirth (2000).Brazil (1985).
THX-1138 (1971).
Dogville (2004).
The Assassination of Jesse James by the Coward Robert Ford (2007).