Good points all and a great question to ponder.

For me, it's too much when the graphic sex becomes boring, because it does nothing to either further the story or titillate the reader.

If its not furthering the story and I'm not getting off on it, then its wasted space.

I don't want the author to only tell me what's going on, I want them to show me and let me experience the characters feelings. Aurelius, Jeangle, Boccaccio and Powerone do a great job of this.