How to sign a letter

I believe in honesty and integrity, but it's hard to do that when you write letters (in real or electronic ink). Sometimes it's because you're writing a boilerplate thank you note to someone you don't know really well or because your relationship to the receipient is vaguely defined (is she my best friend or just a good friend?)

Here are some suggestions from a German site purporting to teach English. If you want to be mean, you can do it this way.

My comments on ways to sign off:

• "Signing off" - kind of lame and unoriginal, but not offensive
  
• "Goodbye" or "Bye" - communicates a lack of imagination
  
• "Keep in touch" - a good, practical closing
  
• "Love" - I reserve this one for family or significant-other
  
• "Your pal" - one of my personal favorites, informal yet affectionate
  
• "Take care" - parental benediction or what you write when you're worried about your friend
  
• "See you around" - a little too informal for my taste
  
• "Peace" - I don't like this one either
  
• "Cheers" - seems kind of old-fashioned
  
• "Fondly" - parental benediction
  
• "Regards" - seems kind of impersonal
  
• "Kind regards" or "Best regards" - a little less impersonal than "regards"
  
• "Later" - I have better things to do than write to you
  
• "Best wishes" - a rather formal closing (teacher to student, colleague to colleague, etc.)
  
• "All the best" - parental benediction or to someone you like but don't know that well
  
• "All my best" - a bit more personal than "all the best"
  
• "Best" - someone who isn't good enough for "all the best" or maybe someone who was in a rush
  
• "All the best and only the best" - overdoing the "best" closing
  
• "Good luck" - an informal way of wishing someone the best
  
• "Good skill" - obviously you don't believe in luck
  
• "Sincerely" - what does that mean anyways? Would you write an insincere letter to someone?
  
• "Yours truly" - truly what?
  
• "Where did I put my brain" - psychotic closing (only use for very close friends or family)

Maybe it's better just to sign your name and not worry about the closing.