Not sure if it has been posted before but here there are:

Welcome video
http://www.youtube.com/watch?v=X0z2i83fmMk

I forgot my user name or password
http://www.youtube.com/watch?v=GUQthMcBGww

How do I upload a video?
http://www.youtube.com/watch?v=GTYkfApfJD8

How do I make a video?
http://www.youtube.com/watch?v=Apadq9iPNxA

The video won't play—what's wrong?
http://www.youtube.com/watch?v=uCeXNzI_i9g
  
Why isn't my video showing up in search?
http://www.youtube.com/watch?v=uiTEHiXmSKY
  
What's the best format to upload for high quality?
http://www.youtube.com/watch?v=32T2Hn7KFo4

Which one do you like most?