Reddit: What are your opinions on 9/11 conspiracy theories? (And conspiracy theories in general)

I have always thought, as with most conspiracy theories, that it's all bullshit and it was simply a case of crazy terrorists doing their crazy thing but apparently some fella in the UK managed to evade a TV licencing by claiming that the BBC reported the building 7 collapse 23 minutes before it actually fell(!?). It sounds crazy to me and just "another conspiracy theory" but it does ring bells in my head that indicate that maybe, just maybe that is more to this than meets the normal logical, rational persons eye.

Here's the video I just watched: http://www.youtube.com/watch?v=EZBM-pkJPio

Note: I do not follow any conspiracy theories and I consider those that do pretty damn insane. Also, I'm not saying I now believe in 9/11 conspiracy theories or any conspiracy theories but...I'm intrigued with it all. I had a pretty intense argument recently with a work colleague regarding these theories in general (especially moon-landing hoaxes - crazy IMHO), so this is a general question - are they mad or is there some deeper truth 'out there'?