Oooh, love that 47 one!
Also love Sazzy's "Bad Moon Rising". I laugh out loud every time I see the tree fall on Chakotay's head.
Nathasja's "Trick or Treat" is excellent. I swear I made "Afraid of the Dark" before I saw it. I was a little embarrassed later when I saw how similar the opening scenes are.
Here's another cool Halloween video, both Voyager and Enterprise.
"This is Halloween"