Rules of Writing

I'm going to guess most writers have some brand of style book hovering around near their writing desk.  You can even find style books online.  In them and in any other number of reference sites, books and classrooms, you can learn the 'rules' for writing.

This quote was in the monthly newsletter for Pennwriters:

"There are three rules for writing the novel.  Unfortunately, no one knows what they are." - W. Somerset Maugham

The longer I'm in the business of writing the more I believe in that quote.  I'm not sure when I realized ending a sentence with a preposition isn't really a sin though lots of editors don't like it.  Let's face it though, when we speak we end sentences in prepositions all the time.  Some sentences sound better with the preposition at the end.  How many of you have had editors who insist you don't have a single of, from, or whatever before the period.

I had an editor who insisted I remove every 'being' from my manuscript even the ones like, 'human being.'  She frustrated me a little.  Another editor insisted throughout an entire 450 page book that I should refer to the horse in my book as 'he.'  She wanted the stallion to always be called 'it.'  I threw a few things when I worked with her. 

How about not starting a sentence with a conjunction?  But I do this all the time.  And so do lots of authors, many of them very successful.  Because sometimes starting with a conjunction conveys the meaning the author wants.

So what 'rules' of writing do you break on a regular basis?  Which rules don't you like to see broken? Have you ever had an editor or critique partners who insisted you break no rules?