I have never understood this "controversy". If I were a devout Christian, I think I would be offended to have the celebration day of my religion's Savior turned into nothing more than a sales gimmick.
Also, if you believe Christmas to be a soley religious , albeit traditional, celebration, then I'm afraid you are in danger of creating a state religion. Bad idea, that. So please, practice your faith. Keep your traditions. But don't confuse commerce with religion.
As for the whole "Happy Holidays" thing, Christmas is one day out of what has turned into a season that includes everything from the day after Halloween to the day after New Years. When I work in the public, I say "Happy Holiday" less in an attempt not to offend than attempting not to get confused - after all when you are hearing Jingle Bells, Thanksgiving is not what comes first to mind.