So, we want marketing attitudes in IT positions? We want bright, perky accountants, and dishwashers who whistle while they work.
As an IT tech who has endured both perceptions of a 'nice guy' and an abrasive tech, I would say a lot depends on what you demand of your employees and how you interact with them.
If I am being attacked because the users I am trying to support are 'know-it-all' smart mouths, then I tend to get a little defensive. If I am trying to help someone who genuinely wants and appreciates my efforts to bring them solutions (usually to problems they generated) then I tend to be more concerned about them and am willing to go extra miles for them.